> It seems like Supabase has been able to collaborate really effectively with other teams in the Postgres space (including pgAdmin and pgmigra, for the `diff` migrations tooling)

I'm thankful to Supabase for their efforts, but I'm not sure I'd pick pgAdmin and migra as examples of "really effective" collaboration with other teams: as far as I know, pgAdmin's CLI feature wasn't merged upstream and sits in an outdated Supabase fork of pgAdmin which doesn't fully support Postgres 15, and migra (which has been abandoned for a while) was just used as-is.