I’ve mentioned this elsewhere but it could just be a UI thing handled by/for each user, that way moderation and control will stay where they are
Basically I could make a group of communities/magazines, for example
selfhosted@kbin.social
selfhost@lemmy.ml
selfhosted@lemmy.world
selfhosting@chirp.social
selfhosted@lemmy.ml
selfhosting@slrpnk.net
For browsing, up/downvoting, and commenting it could be totally transparent. When you want to make your own thread it could just have you select the specific magazine/community from a drop down.
This wouldn’t fix the problem of seeing multiple duplicate posts from each.
Yubikey is a good option. It supports totp for sites that don’t support physical keys.