I recently learned that voting on lemmy is not anonymous. Anyone can get information about who has upvoted and downvoted a post or comment.
In combination with your IP, this is a massive privacy (maybe even physical security) risk. Also, people can target you for your votes.
Sadly, this is something where I would prefer Reddit over Lemmy. Big tech scrapes data from both places anyways, at least Reddit is safe.
The IP address thing is not real, though
Just choose a nickname that is random word+4 random digits and don’t reuse it on other services
This is the way. Randomise your usernames and use a password manager to keep track of them.