Nowadays there are "language editions" (e.g. GHC2024) packing many stable language extensions together. It's definitely safe to turn those on, from a maintenance point of view.
Yeah - we definitely consider the language edition as we revise our internal lang extension rules...but we still find ourselves even a little more conservative than even GHC2024.
Edit: Link to docs: https://ghc.gitlab.haskell.org/ghc/doc/users_guide/exts/cont...