Ok, what a fucking mess. Seems something changed or something is different now, but:
pgbouncer auth user must have md5 password set and md5 allowed to use for this user only. then logins will work with the SCRAM passwords for the normal users. Meh. what a gagsi #PostgreSQL #PGbouncer
I understand that now what that doesn’t work and never will work. Need to investigate some other plans …