ModdIt
Interesting is if you are on Arch or Arch based the argument against AUR is stability, same as put to discussion here.
The big but is Installing software form other sources or self compiling are user choices.
Note what you install, better not a big bundle of unsupported applications at once, that makes finding troublesome packages a pain.
Get desktop freezing, do you have ungoogled chromium installed, common culprit due cache or config corruption. Libreoffice Fresh and Debian Java. Debian java is buggy (known lt devs fixed next release) and not in the LO approved list it can cause hard to diagnose issues. LO approval maybe after a bugfixed java release.
As blur 13 wrote trade offs, user choices.
PPC gave a number of links for appimages, Personal opinion is if software can be downloaded from the original source as a deb it is better to do so. Firefox, all versions portable from Mozilla, plus debs from repos. Opera, Vivaldi, debs available. Libreoffice Fresh Backported debs or if java is really important from LO org. Deb packages easily installable with dpkg. Softmaker, packet installer or direct from softmaker site, debs and instructions available.
For packages which are only available as appimage and have checksums, I like to look in the package then try them on an isolated system before using on my main device.
An equivalent to AUR, I would certainly use it knowing the advantages can be outweighed by problems. Big but there is we have a fantastic live system on a stick available, best playground or testing area possible.
I used AUR quite a lot, had way less less trouble than with systemD, crazy waits for shutdown, sticking boot process and non recoverable update fails which were a plague for a while. Not to mention that if you wanted to remove some seemingly unimportant application like a music player the d madness would also wipe out your desktop. Real experience, it was, i guess still is lunatic.