It can be set up in a day if you slap traefik infront of it, change the env and compose files a bit and run it with docker compose.
I admit, I already had a working mail server and wildcard LE cert... let's say you'd need the other half of the day too to set that up if wanted.
Personally I set it up in a way such that the studio is not publicly accessible but can be accessed using ssh port forwarding.
All in all, I still agree that it's not really user friendly to self host it. It's basically only one supabase project. But in reality, it shouldn't be that hard to create new template dbs in postgres to set up multiple projects and also provide a good UI for that. They don't bother to provide that functionality though for I believe obvious reasons.