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.
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.
I'd bet it is a typo stating ddr5, not on the CPU model. 8GB sticks of ddr5 are rare enough to find as singles, and 4gb sticks basically don't exist - makes more sense if it is a DDR3 system. Plus, the GT 730 is basically only barely a graphics card, a lot of them are Fermi based chips (like gt 400 series from 2010)... They are dirt cheap video output for a machine that otherwise wouldn't have any video out, but they get packaged by less than honest companies/people with other old hardware and marketed as "gaming computers" all the time unfortunately.
Ubuntu is not the limiting factor to this machine gaming, unfortunately. It is going to be choking itself on basically any games from the last 10 years :(
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!
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
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.
I've been using Arch for over a decade, and I would advise you to be careful when upgrading nvidia drivers. They just break every so often. Just do not delete your pacman cache and you should be able to easily downgrade