KeepassXC. I like to keep things in a physical file. It also supports key files

And how would for example “mastodon.social” learn about my instance and show my toots to their users? Should someone from “mastodon.social” to search for me explicitly?

Thanks for a detailed explanation

Any platform that requires your phone number to sign up can’t be considered private de-facto

Sounds crazy and interesting. Although, isn’t it better to have separate things for separate type of content (videos, toots, posts) instead of mixing it all together?

And also saves trees