First question - if you’re not using BTRFS why didn’t you set your Timeshift to an external drive? If you do a fresh install/wipe the disk, you can restore a timeshift backup.
Now there are a couple of ways to manage this without fresh installing.
For a quick method, start using PlasmaConfigSaver.
If you create a TEST user, it uses the template from /etc/skel. You can use that…
Create a folder in your /home directory called DOTCONFIG, then MOVE all of your hidden files into that folder, log out and in and you should get a pretty clean (like TEST user) desktop. You can include as much as you like - but mostly .local and .config are important (see linux-aarhus post).
After this, you copy important stuff from your DOTCONFIG/.config and .local folder taking care not to copy the problem files back.
I like PlasmaConfigSaver, but it has issues - for example I set up a nice NORD theme, with kvantum, matching default Konsole and Yakuake etc. I also set up EventCalendar with my Gmail and a nice blue-grey font for the time and dark grey for the day/date - I set these up with a custom Latte setup.
I saved 'Nord-2021-03-18 using a date to define the exact save, and if I edit this Nord theme, I can save it with a new date/time.
Later I set up a new theme and setup, and realised that restoring Nord overwrites ALL of the settings (including the EventCalendar/email/colors etc) and is a slight problem…
Basically it saves all the autostart, color-schemes, icons, kvantum, latte, plasma, wallpapers, and rc files (dolphinrc, kcminputrc etc) and it isn’t conservative (I mean if you set Nord, it won’t just save NORD - it copies the entire folder recursively).
The same can happen using Timeshift - you will overwrite everything, including documents, so make sure stuff is backed up first.
I do include my entire /home directory in the timeshift snapshots - that simply means I must take extra care before restoring, I might need to take a new snapshot or backup if I was working since the last snapshot. The other way of dealing with this is to keep your work somewhere else and regard your boot drive as a mostly system drive and less of a /home.
I’ve seen FerenOS has enhanced the KDE settings to include a ‘layout’ switcher, which you can do with PlasmaConfigSaver. Save one DEfault, then work on your desktop and save a new version for easy switching. You can easily delete them later.
I’m curious, with PlasmaConfigSaver - is it easy to load up a ‘foreign’ config? You could try if you like: Dropbox - Plasma-config-Nordic.tar.gz - Simplify your life