Have you heard of Dwarf Fortress?
Seems to be an old Caves of Qud which is free, but that might be fine by me:)
https://freegogpcgames.com/4525/caves-of-qud/
And here
https://archive.org/details/caves_of_qud_2_0_206_78_73562_gog_linux
Discussion
Yeah, I was wondering if that would be a good place to start as a total beginner to the format
Oh boy, not sure. I tried the free version, and couldn't get into the interface.
Also not free, but if you want a roguelike that is simple to play, hard to master, and is a ton of fun, check out Legend of Dungeon.