Can only speak for me:
Did convert all 3D movies with the help of a tool called BD3D2MK3D. There’s a thread here in the forum. My environment Fire-TV 4K Ultra connected to a 3D capable LG TV works like a charm.
Some drawbacks:
You can no longer play these converted 3D movies in 2D.
If you want 2D and 3D releases of that same movie, you need to put them in different libraries. If you put them in the same folder, Plex chooses automatically, and that won’t work.
And I do experience problems with metadata if you have that same movie in two different libraries. Plex forgets the covers after a metadata scan from one of both.
Edit Found the thread:
