That's the problem with pseudo-anonymous platforms, since every post is logged into a single account it becomes possible to trace completely unrelated posts on unrelated threads and in this case even communities and instances, even to the point of stalking.

And the more posts you write the more information a hostile actor has to be able to correlate information. It's really bad for opsec, since there are no reason for two different posts on two completely unrelated threads to be linked together.

Anonymous image boards are usually much better in that regard, unfortunately chans are nazi bars, so I stopped using them years ago, my guess is that they are also difficult to moderate (though usually the mods are nazis themselves).

What I recommend doing is keep using lemmy but delete your account and make a new one from time to time, I usually do that with every website that requires a login anyway, abandon all old accounts, clear all cookies and browser data, (and apps if you use them), turn off my router overnight so I get a new IP and start anew, make a new email and register new accounts to that email.