Xfce

https://xfce.org/download

I hope they would include addon sideloading as well

Yep, too overly specific or weird on some stuff, like for example on installing packages via terminal, I just went with suggesting it because I haven’t fully red and understood your query, my bad :)

As for auditing tools, I can’t think of any because there is a lot of ways how to check logs and it is messy ngl. If I’ll be honest with you how I kinda survived linux is by automating backup of important files through nas and if I f*cked up my system, instead of fiddling the logs to find what went wrong, I’ll just nuke it.

Opensuse has GUI frontend that controls almost all the system settings called YaST, why dont you give it a try