I am just a regular Linux user with a bit of additional interest in customizing. I can install things from the store, change settings in the GUI comfortably etc.
Occassionally there are things I am looking for are not available already but could be with few simple tweaks. For eg. right now I am looking for an analog clock widget different from the standard one already available. I need to reduce its size and/or change its background.
I believe this could be done by changing the clock source and building a new clock.
Currently I am not knowledgeable enough to do that and also with insufficient free time to learn everything. I would try if there is a standard pre-built ISO configured to this need with all tools pre-installed.
Gentoo supports slots; which allows for concurrent installations of things like desktop environments. Not sure if it's configured that way right now though.
If you use BTRFS you could install gentoo on a subvolume and boot into it when needed too.
@arran4@voracread With some specific packages there are conflicts between different versions, so you can only have one at a time installed even if they have different slots. I think a few of the core KDE packages are like that. I know that I had to remove some parts of KDE 5 when I installed KDE 6 on my Gentoo system.