dell xps 13 9310 laptop with Intel i5 evo processor and I think 8 GB of ram
That should be fine.
I am currently using linux mint 21.2 with cinnamon desktop.
That should be fine as well.
I believe I have installed apps outside of official repos, sometimes successfully other times not. I try not to do that though.
Have you considered installing those apps inside of a container? Distrobox is worth mentioning as it streamlines a lot of this process and even allows one to set a ‘distrobox’ with its own custom HOME directory. It should make experimentation a whole lot less painful, so you should definitely think about it if you haven’t yet.
I’d argue that if you reinstall Linux Mint with TLP -for what it offers in terms of battery life- and install the exotic packages within a distrobox, then most of your concerns would be resolved. Maintaining a healthier system like that should also decrease the rare bugs that you might be facing right now and thus enable you to run a system over a longer time period.
If this course of action makes running your distro too boring, then it’s probably worth exploring either Arch or Gentoo as a dualboot alongside Linux Mint. Linux Mint would be used for school/work or whatsoever, while Arch/Gentoo is where all the ‘fun’ happens. Both distros also play a lot nicer with packages not found in the official repos, so they should necessarily offer a better experience.