I am not satisfied with Linux's security and have been researching alternative open source OS for privacy and security So far only thing that's ready to use is GrapheneOS (Based on Android) but that's not available on desktop (Though when Android release Desktop mode it may become viable)
Qubes OS is wrapper around underlying operating systems, so it doesn’t really fix for example Linux’s security holes it just kinda sandbox/virtualize them
OpenBSD is more secure than Linux on a base level but lack mitigations and patches that are added to linux overtime and it's security practices while good for it's time is outdated now
RedoxOS (Written in Rust) got some nice ideas but sticks to same outdated practices and doesn't break the wheel too much, and security doesn't seems to be main focus of OS
Haiku and Serenity are outright worse than Linux, especially Haiku as it's single user only
Serenity adopted Pledge and Unveil from OpenBSD but otherwise lacks basic security features
All new security paradigms seems to be happening in microkernels and these are the ones that caught my eyes
None of these are ready to be used as daily driver OS but in future (hopefully) it may change
Genode seems to be far ahead of game than everything else
Ironclad Written in ADA
Atmosphere And Mesosphere Open Source Re-implementation of Nintendo Switch's Horizon OS, I didn't expected this to be security-oriented but seems like Nintendo has done a very solid job
Then there are Managarm, HelenOS, Theseus but I couldn't figure out how secure they are
Finally there is Kicksecure from creators of Whonix, Kicksecure is a linux distro that plans to fix Linux's security problems
if you know of any other OS please share it here
Many Flatpaks bundle libraries which aren't available in any runtime. There have been cases of non-malicious Flatpaks (on Flathub) containing known vulnerable versions of libraries. Is a user expected to cross reference a Flatpak's manifest with known library vulnerabilities before installing it?
Flatpak's "sandbox" (more of a container really) also breaks internal sandboxing mechanisms used by some other apps notably Chromium-based browsers (they use some hack to use Flatpak's sandbox instead but I doubt it is as secure).
Flatpak is not a security tool, it is a software distribution tool (Edit: BTW, the Flatpak project doesn't even claim to be about security).
Let's improve flatpak, instead of abandoning it :)
Personally I don't see the harm in abandoning Flatpak, the technologies developed to support it (bubblewrap, desktop portals and the secure contexts Wayland protocol to name a few) are far more important and can be used independently.
I think Flatpak has the potential to be good, if distros use it as their primary package manager with a sane (not Flathub) repository (Fedora has a well maintained Flatpak repo, for example). Otherwise, for the average user, installing a Flatpak from Flathub when there is a distro package available might seem like a good idea because they heard about sandboxing, but in many cases it will actually be more secure to just use the distro package.