Lemmy admin should add option in the account settings for hiding your username from your posts/comments, and hiding your profile from the public, so noone would be able to see all of your posts in your profile page, and even if someone is using a tool for scrapping posts, they wouldn’t be able to link the posts to 1 user, because the username would be greyed out “anonymous” (and would not link to anywhere). Only lemmy staff would know the real username.
Edit
This feature would be useful for whistleblowers, or users who want to be anonymous (those who often delete their posts/comments and accounts, or have to use multiple accounts to reduce fingerprinting), while others who want to use lemmy as social media and create friendships would keep their username visible publicly.
You’re better off rotating usernames on a semi-randomized schedule if it really matters to you that much. Is your personal threat model such that you actually need to be concerned about this?
Anyway, OpSec rather than asking others to fix your privacy concerns would be the way to go.
Create separate accounts by topic, with different fake identity details beyond what you made them for. Keep track of each identity’s fake time zone when planning when you post so that no one can figure out what time zone you really are posting from.
Beyond that decide on a lifetime (and “cooloff period” before you make a replacement) for each account using a random number generator.
Most importantly, use various AI tools to obsfucate your typing style and word choice.
This all seems like a shit ton of work to just talk about your hobbies. I sincerely hope you don’t have stalkers this dedicated.