Or would concentrating my lemmy/piefed use strictly through a self-hosted one person instance account help to ensure nothing but what I’m ‘intentionally doing’ is tracked?

It would ensure that yes. The other instance would only see the IP of your instance, not browser information or anything else. I haven’t tried selfhosting, so I can’t speak to it’s difficulty, but as far as I know, there is no reason to distrust any of the major Lemmy or Piefed instances. I’m not an expert and it is open source software so anyone could theoretically edit the code if they wanted.

And privacy refers to having control over who can see your personal information, anonymity means being unidentifiable.