New features, fixing bugs, security fixes, hardware support, etc. Why would Linux updates be different than updates to any other OS? 

All OSes are a collection of lots of different software that work together to run your system.

For Linux distros, that includes kernel packages (the core of the OS), but also a huge range of software to make the desktop work, apps you run (office software etc) and more. They are all separate projects, constantly working on and releasing updates at their own paces. There are new software releases all the time for all sorts of things.

If you install a Linux point release Distro, like Ubuntu 22.04, you get the OS and a snapshot of lots of different software they have chosen to package. Then after install you will receive constant minor patches and security updates, but the main software doesn't get major updates. For example, if Ubuntu uses say version 1.0 of your desktop (e.g. Gnome), and the Gnome project then releases 2.0, you won't receive that. You'll just receive patches and security fixes for KDE 1.0, but not big updates for new features or changes. This allows Ubuntu to keep 22.04 stable and working predictably for people, and means they don't have to retest the whole OS to make sure it works and stays secure. All they have to do is test the security patches, make sure those work well with the existing OS and then release that to users.

But overtime Ubuntu 22.04 inevitably falls further behind all the major releases of the software they use, and people are missing out on more and more new features, more major bug fixes and more. The desktop environment for example might have released version 2.0 with new features, and the Office software may have released 2.0 with new features, and 100s of other components the same even in just 6 months. So the distro maintainers then build a whole new version of the OS with all the big changes they want to include, and release that as 22.10 in October 2022 - this is their next 6 monthly point release. People can chose to stay on 22.04 and just get security patches (so the OS is stable and safe) or decide to move their PC to 22.10 and get the newer software.

This is a constant process. Ubuntu is on a 6 monthly release cycle, and people can chose when they want to switch; they can do it every 6 months or less frequently if they want. Ubuntu and other distros also have LTS releases - Long Term Service releases - if you use that version, it is maintained for a few years as is, except for patches and security updates. Not everyone wants the latest version of software, they may just want something that they know works and they get on with using it.

Another model is rolling releases where the Linux distro constantly rolls out new updates for all the components. This can even be weekly, or near enough daily; for example OpenSuSE Tumbleweed is a rolling release. People might not update every day but the maintainers are constantly rolling out the latest versions of software (after some testing to make sure it works) so that end users can keep bang up to date on near enough everything. This is riskier than a point-release, and sometimes bugs get through that have to be undone, but it allows those who want cutting edge systems to have them. OpenSuSE also have a point release version Leap which updates once a year, and is also developing Slowroll which works on a monthly release cycle.

Windows actually does something very similar to the "Point Release" system for new features and major changes, although the updates are all closed source and under Microsofts control. Windows 11 has had major annual updates 21H2, 22H2, 23H2, 24H2, and now 25H2. One big difference though is that Windows updates are only Windows and Microsoft provided software; all the rest of the OS including drivers the user has to update (or sometimes Windows Update manages). On Linux, much more of the system is usually updated by the Distro, and the user generally updates a much smaller proportion themselves (e.g. maybe their Nvidia drivers, and their flatpaks).

The big point releases are not about increased security, they are instead more about getting feature releases out to users from lots of different projects. The security side is managed by constant patches and smaller bugfixes rolled out within each major version.

If you're on a 6 monthly distro, you probably won't notice big changes, you'll more likely see lots of smaller changes. The really big changes (like KDE moving from 5.0 to 6.0) are less frequent - maybe every couple of years - while the smaller but still substantial changes are frequent - like 6.2 to 6.3. You will notice when you move from 5.0 to 6.0 but when you move from 6.2 to 6.3 you'll have lots of smaller nice changes but not a major change to your desktop. So while it seems like little is changing, lots of small things are changing all the time.

This is how updates should be. Important fixes and security and not change for change sake. improve the ui or such when you have actual improvements. I mean most ui improvement to is with the window manager not the os.

Same as anything else. Security updates are the new antivirus, but baked in. That's the most important reason.

There are new features that you may not notice or use. But think about it, support for new resolutions, refresh rates, cable standards, VRR, HDR, drivers for new hardware and USB devices, improved drivers for existing hardware, bug fixes. All of this has happened within the last few years. Not to mention visually obvious changes like redesigning the Ui, aesthetics, adding new baked in programs.

You mean for the Linux kernel specifically? Linux distributions?

For software in general

not Linux-specific

updates fix bugs (some of which might be security-related). Adds features.

That may be too general to be useful, but the question doesn't have much by way of specifics.

I feel like maybe more context would make for better answers. Like, if what you're asking is "I have a limited network connection, and I'd like to reduce or eliminate downloading of updates" or "I have a system that I don't want to reboot; do I need to apply updates", that might affect the answer.

EDIT: Okay, you updated your post, and it sounds like it's the Ubuntu distribution and the new release frequency that's an issue.

Well, if you want fewer updates and are otherwise fine with Ubuntu, you could try using Ubuntu LTS.

https://ubuntu.com/about/release-cycle

LTS releases

LTS are released every two years and receive 5 years of standard security maintenance.

LTS releases are the go-to choice for users who value stability and extended support. These versions are security maintained for 5 years with CVE patches for packages in the Main repository. They are recommended for production environments, enterprises, and long-term projects.

You'll still get security updates, but you won't see new releases on a six-month basis.

It can be nice to have a relatively-new kernel, as it means support for the latest hardware (like, say you have a desktop with a new video card), but if you have some system that's working and you don't especially want it to change, a lower frequency might be preferable for you.

I use Debian myself, and Debian stable tends to have less-frequent new releases. You'll normally get a new stable release every two years, with inter-release updates generally just being bugfixes, and new stuff going in every two years.

https://www.debian.org/releases/

Debian announces its new stable release on a regular basis. The Debian release life cycle encompasses five years: the first three years of full support followed by two years of Long Term Support (LTS).

EDIT2: If you already have Ubuntu on your system and only want LTS updates, it looks like this is how one selects notification of new LTS releases or all releases.

https://ubuntu.com/tutorials/upgrading-ubuntu-desktop#5-optional-upgrading-to-interim-releases

Navigate to the ‘Updates’ tab and change the menu option titled ‘Notify me of a new Ubuntu version’ to For any new version.

EDIT3: I'd wait until an LTS release to switch to LTS, if you aren't currently using LTS, so that you aren't on a system that isn't getting updates. Looking at that Ubuntu release page, it looks like 26.04 is an LTS release. The Ubuntu versioning scheme refers to the year and month (26.04 being the fourth month of 2026). It's the third month of 2026 right now, so the next release will be LTS, so switching over to LTS notifications now is probably a good time. You'll get a release update notification next month. You do that update, and then will be on LTS and won't receive another notification again for the next two years.

Such a thing is actually quite enormous in terms of the sheer number of little details. Its like updates to maps. There are constantly little fixes and changes and improvements to the online maps of your country, but how likely are you personally to ever notice any of them?