How advanced is the project regarding self-hosting?

Self-hosting gets you exactly the same as you would on the hosted/managed platform, but you have control over the power of the system/VM you host it on. Any project you'd host on normal supabase you could host on self-hosted. In my use case, it was cheaper for me to self-host (due to the amount of data I need to store) and also gave me finer grained control over performance since I can apply custom postgres configs. So yes, you can use self-hosting for serious projects.

Thank you! Just wondering how are you securing it's web panel since it doesn't have any login system. Are you just not exposing it's ports to the Internet?

You can configure the docker compose file to listen to localhost only for the Studio host port, instead of the default all interfaces.

Mmm it might be good enough

Yes. I wrote a guide last year on setting it up and using nginx to expose Supabase via a domain. It still uses Kong which is included as part of Supabase, but I found it easier to configure Nginx to point to Kong instead of pointing directly to each services: https://dev.to/chronsyn/self-hosting-with-supabase-1aii