If you treat privacy as all-or-nothing, "total privacy" would imply no one has any kind of information at all about you. The only way for no one to know who you are is to completely disconnect yourself from society.
Rather than thinking in terms of "total privacy", you should just aim to be as responsible as you can with what information you share with who, while recognizing that participating in society is itself a compromise you are already making. If your end goal isn't to completely hide from the world, then don't make yourself miserable trying to pursue that.
I thought Kbin had the most potential, but even after it was reborn as Mbin it does feel like it's been largely forgotten. Interstellar's alright, but I'm not super in love with it and it doesn't look like anything else plans to support it.
Piefed has gotten all the attention now, and I keep eyeing it wondering if the grass is greener.
I'm never touching Lemmy thanks to its devs though.