The requests (RedLib links):
https://farside.link/redlib/r/fediverse/comments/143j1j8/is_there_a_3d_metaverse_of_the_fediverse/
https://farside.link/redlib/r/opensourcegames/comments/rdub3p/comment/ho43ld1 (link to comment)
The discussion:
https://lemmy.ml/post/87083
https://farside.link/redlib/r/fediverse/comments/iad25v/any_good_federated_gaming_platforms/
https://farside.link/redlib/r/gamedev/comments/12e7fum/game_on_fediverse/
The rejected Minetest suggestion:
https://github.com/minetest/minetest/issues/7993
A blog
https://kevinhoffman.blog/post/fediverse_gaming/