So I got Pleroma working with pgbouncer, so I've got that going for me, which is nice. In case anyone cares, or finds this post in the future, this is what you need in pgbouncer.ini

ignore_startup_parameters = gin_fuzzy_search_limit, jit, plan_cache_mode

Instead of 'imposter syndrome' I get 'I'm a better DBA while drunk than most people are sober' syndrome.