For micro/personal server runners, I built a tool to automatically discover and add communities to your local instance :)
https://github.com/lflare/lemmy-subscriber-bot
Just for context, subscribing to about ~800 communities, of which have about more than 50 users/month, my metrics have indicated a disk space usage of about 2GiB/day, 20% of a single CPU core, and about 8~10GiB/traffic a day.
Unfortunately, it seems that most of the disk space used is by a single database table used primarily for debugging, thus once that issue is fixed, the disk space usage should drop dramatically into maybe just a hundred MiB a day or less.
EDIT: For support requests, I've created https://lemmy.world/c/lsbsupport as well.