@talesofaprinny @kde I'm not sure how helpful this will be for you, but it's kind of like email. You have an account on one email server (like, say, Gmail), and you can use that account to exchange messages in a standard format with people on other email servers (Outlook, Yahoo Mail, Proton Mail, Fastmail, etc.), but your account on Gmail doesn't let you log in anywhere else. If you want to use any of those other servers directly, you need to create an account on the server you want to use.

Similarly, you can use your account on one Fediverse server (mastodon.social) to exchange messages in a standard format with people on other Fediverse servers (techhub.social, lemmy.kde.social, etc.), but your account on mastodon.social doesn't let you log in anywhere else. If you want to use any of this other servers directly, you need to create an account on the server you want to use.