You should have backed up saves prior.
Uninstall or remove mods.
Go to the hdd saves directory and make a new folder name it backup dated etc cut and paste all saves into that new folder.
Disable cloud saves.
It will be a new start of the game.
Start game check settings and options I guess.
Cloud saves reflects the saves on our HDD you can perminently leave cloud off if you backup your saves on the HDD.

Well most of the time game mods and game settings is 2 diffrent things.
so are you sure its not 2 diffrent pc spec you mix up in this as well, then you play from 2 diffrent device or something like that.

ps.
keep in mind we dont read the same or think on same term here, Jaunitta might be spot on, but same time wrong if its 2 diffrent pc setup you play from. and thats still OP missing info that could lead to such ways.

Exact same problem here. Steam cloud just decided to turn itself on, when I keep it off, and it deleted my save games and settings for rimworld, filling it with data and saves from 2017.

Steam NEEDS the option to delete saved cloud data.
And it shouldn't have turned itself on again in the first place, because I always keep it off.