Everything was working so far but I couldn't upload an avatar. From within Supabase Studio I saw, that the created policies from the tutorial wheren't tied to any bucket. So i tried to manually create a bucket and received a "NetworkError when attempting to fetch resource.".
I tried it with other Browsers (Safari, Chrome) and received similar errors (Failed to fetch, Failed to load). Apparently a CORS error. But I couldn't resolve it further (tried it with another network and even a new account, all the same).
Supabase gives you the tools, documentation, and community that makes managing databases, authentication, and backend infrastructure a lot less overwhelming.