Lol then allow me to put your mind at ease:

Lemmy.world (LW) is the #1 instance with >16k MAUs (monthly active users)

lemm.ee btw was the #2 instance with 5.3k MAUs, roughly a third the size of LW

lemmynsfw.com is #3 with 3.6k

sh.itjust.works is #4 with 2.8k, 5.7-fold smaller than LW

fwiw Lemmy.ca is #7 with 1.6k MAUs

PieFed.social has 684 users total, as in <0.7k MAU, 24-fold smaller than LW

All of this according to Fediverse Observer stats (not that easy to use especially for PieFed, which it doesn't even have an icon for, and doesn't allow sharing of URLs for the sorting and filtering options very unfortunately).

TLDR: nothing across the entire Fediverse comes anywhere close to Lemmy.world in terms of users.

PieFed is gaining ground because the features are just that good in comparison to Lemmy, and because the admins are not authoritarians. Indeed, do look into it, bc it's well worth knowing about, and you may fall in love and switch yourself:-). I did.🥰❤️