There's not really a centralized collection of everything, but this /r/subredditdrama post is probably the most inclusive of the information.

https://www.reddit.com/r/SubredditDrama/comments/atmzuj/rskyrimmods_1_modder_for_bethesda_games/

There's quite a lot of trouble.

To name a few, making older versions of the Unofficial Patches unavailable and deliberately breaking compatability with SkyrimVR, then filing DMCA takedowns for people rehosting those old versions (also note that the permissions for the mod allowed rehosting at the time).

The controversy referred to as Gategate where the Open Cities mod (by Arthmoor) adds broken Oblivion Gates to the cities and caused the removal of any mod that reverted the change.

Lastly, there's a program called Wabbajack. An automatic modpack installer that predates Nexus' own Collections feature. On its release, Arthmoor and team removed the current Unofficial Patch and replaced it with an automatic installer executable (like those auto-extracting archived files) claiming that "this is what people want clearly because Wabbajack is an .exe installer."

I actually found another /r/subredditdrama post on that last one too if you wanted to read up on it:

https://www.reddit.com/r/SubredditDrama/comments/d9abn8/you_have_committed_crimes_against_skyrim_mods_and/