For me, it’s Shared GPU memory.
I believe that’s due to package drift.
Every system starts with the same packages, but due to upgrading or adding/ removing stuff, you slowly drift away from the starting point, which makes it truly “your own”. But this also introduces bugs that aren’t reproducible.
I especially noticed it with KDE. Every time I installed a new distro or configuration, it worked fine, but after a few months, the bugs and crashes got more and more.
Since I installed Fedora Atomic (the “immutable” variant, e.g. Silverblue), everything just works. It’s extremely comfortable and just exists, so I can run my apps. When you upgrade the system, you don’t just download one package and install it, you apply it to the whole OS and then basically have the same install as all the thousands of other users out there, which makes it reproducible.
Maybe that’s something for you? You can check out Aurora, Bazzite or uBlue in general.
I already thought about that, but never really could justify switching.
I would argue, though, that it’s not customization, but rather packages themselves changing over time and sometimes just break.
And sometimes you have crap like a full boot partition, because apt decided to keep all Linux versions for some reason.
