Welcome back @MrScrith.
Is /home reused from previous installs of some other distro?
Two things to look at for this:
What to do if there is a problem installing OMLx
Do an internet search of ‘Linux permissions’ without the tick marks and learn how to discover what permissions are and change them if needed. This is not that difficult. There can be a lot to do though because lots of things have their own permissions.
An alternative would be to start over with a fresh formatted /home. But I can not say from the information I have that that is for certain the problem just that it might be.