@Eureekaaaa
There are a lot of users on this server who can't (or won't) read non-Japanese texts, and most non-Japanese posts are ignored (and sometimes muted), but that doesn't mean they're denied.
However, mstdn.jp has many inconveniences for non-Japanese users (e.g., lack of some new features because server version is old, server-specific glitches, Mostly post in Local/Federated TL is in Japanese, etc.), so I would recommend using a different server simply for the sake of convenience.