With that kind of hardware, nothing you could tweak would help a whole lot.

You need an upgrade mate.

I agree with the other posters, your hardware is going to hold you back. But you could try switching to a lighter desktop environment like LXDE instead of GNOME. This user found a small increase in performance: https://www.reddit.com/r/linux_gaming/comments/dg87jp/does_the_desktop_environment_matter_for_gaming/

But they had somewhat beefy hardware. If you're truly at the limit of your specs, 100% CPU/RAM usage, your performance increase could be even more.

Honestly, you’re not going to have a lot of luck with recent games. The sandybridge i5’s were great back in the day but their time has come. I had a 2600 for a looong time but it’s been out to pasture for a couple years now.

Check out the “patientgamers” communities, they like to play older games that would run a lot smoother on your hardware.

Your setup is close to my 2015 very-much-non-gaming laptop, so... I'd recommend retro gaming and/or modern 2D games. A few suggestions would be: Baldur's Gate 1-2, Icewind Dale 1, Xenonauts, Battle Brothers, Wildermyth, Shadowrun Returns (and sequels), Into the Breach, Fallout 1-2. If you're into programming games, that hardware should run everything by Zachtronics as well as Human Resource Machine and 7 Billion Humans.

Into the Breach is a fun game. Command and Conquer 3 and you could get into emulation like Smash bros or Mario Kart.

Stardew Valley

Terraria

Something like Slay the Spire should be easy to run, essential roguelike deckbuilder

celeste and hollow knight

The GT 730 is a very low power GPU, it is even slower than many newer integrated graphics. I'm assuming you mean you have an i5 12400 CPU since you also have DDR5 RAM, which is a good CPU on a modern platform. You should really upgrade you GPU and maybe also upgrade to 16GB RAM as many games require 16GB and having 2 sticks of memory also improves performance by running in dual channel.

The main thing is to game at lower resolution and quality settings as much as possible while keeping . Somebody also suggested gamemoderun and that can help. My laptop with a GeForce 930m can barely run CS GO at 50fps at 720p low settings and the GT 730 is even weaker so keeping realistic expectations will also help you be happier with the performance you have

If you use gamemoderun it optimizes your scheduling to prefer the game to other processes, among other optimizations.

If you don't have a budget to upgrade to a better laptop anytime soon, I recommend using a low ram distro, like Lubuntu and search for the best driver compatible for your GT 730. I believe this GPU barely supports Vulkan so demanding 3D games will mostly not run properly. You'll have to stick with old AAA or indie games. Also, if using a Ubuntu-based distro, make sure the package nvidia-prime is installed to use your nvidia GPU instead of the Intel HD Graphics which are even worse. Good luck!

https://liquorix.net/ might give you a percentage or two in terms of responsiveness.

switch to arch/debian + xfce/lxde/lxqt

also make sure to disable the 2400's iGP in the bios so you're not wasting ram on that

I think your best bet is Gameboy emulation for gaming, that GPU isn't gonna be doing any 3D stuff any time soon unfortunately

1st) quit Ubuntu n use Debian testing, based on your hardware!

Install supertux and have fun.

Also snake and other terminal games should run fine.

1- Switch to Arch Linux (no, really.)

2- Do a minimal installation

3- Search for "arch linux improving performance". There should be a guide in the arch linux wiki regarding some system-wide tweaks via sysctl.conf -- follow it.

4- Also search for "how to enable zram arch linux". Basically, it clogs your cpu a bit to squeeze a bit more of ram out of your system. Follow it as well.

Don't expect any "miracles" out of this... but it should make things more doable/tolerable.

If everything goes wrong, then you can always resort to either geforcenow or xcloud. Or both.