A default installation of Lemmy/Piefed won't track users beyond what they intentionally do on the site. But if you want to be sure, then you can always host your own instance of one person. (In addition to all user activity), other instances can only see the IP of the instance the account is hosted on.
If you want something to be private then well, don't post to the public web (as a reminder- DMs aren't private on Piefed/Lemmy). If you want to be anonymous, then use a VPN and don't repeat a username you used elsewhere.
A power tripping mod is irrelevant to the fact that you knowingly continue to spread disinformation promoting a for profit social media company.
Do not reply to me ever again or I will report you for harassment.