“that's declined so precipitously”

That sounds hyperbolic and unserious.

https://medium.com/flutter/whats-new-in-flutter-3-32-40c1086...

Flutter is doing well on Desktop. Is it going to be the same experience as writing c# on windows or swift on OSX? No. Will it work? Yes.

Note the ffi/jni gen announcement. This has been in works for a long time. FFI has been stable for awhile. The generators are new.