Consider switching the default from evince to papers. The latest
version of evince has switched to gtk4 but papers has a much more
mature gtk4 implementation. The Papers UI is written in Rust.

Unfortunately, I don't know of a way with metapackages to:
- Change the default app when upgrading
- Allow swapping to the previous app after upgrading.

An upgrade script could do that though.

Taking action here would also allow closing https://bugs.debian.org/918921

Thank you,
Jeremy Bícha