I’ve found two possible solutions:

• If you use some kind of Lemmy reader instead of using a browser, it may have a filtering function, like “hide post including this word” like using regex.
• “After complaining yesterday about seeing too much Linux content in the Fediverse” — this Lemmy user seemed to have experienced a similar problem, and finally found a fundamental (albeit rather unexpected) solution. Read more: https://lemmy.world/post/8107430