I don't know if it will scale tbh, but also I don't expect many people to actually self host, and I'm sort of hoping the fediverse stays a bit ... ghettoized. The current threadiverse is like 50000 people and works fine, I'm hoping there will just be more loose communities of 50000 that don't really federate with the main one.
Go low tech, use libreoffice or something to make some card layouts, populate the fields from the CSV with a mail merge, print them and pin them to a wall.
This probably avoids an IT call because you should have these things already available.
I like interactive demos, especially ones that worry people :) But I don't want my instance to get banned so I have to manually approve messages.
Also, to reply to this thread as a guest use this link https://scrapetacular.ydns.eu/post/10170