Is there a description on how to disable pictrs?

Correction, this is the cat that owns you.

Not the other way around.

Management of an instance is very limited and incorporated in the frontend.

I am not a good enough developer to make PR’s to the open source codebase, but someone reading this might be…

I think a replacement of the banned user list by a list of the users on your own instance might help a lot. Makes it easier to navigate to your users and individually manage them (with the tools already available).

However this might scale badly for large instances.

You… can’t. Well only directly via the database if you really want to…