Active users are measured in different ways by different platforms, so if we compare registered users, fedi has 12.5M compared to 42M for Bluesky. So it's approximately 25% of the size.
It's not the best place to go if you want to get a large following, and it's not Serious Business, but as a user that's not what I want from a social platform. I have plenty of people to follow who are talking about things that interest me.
You're welcome to come have a look if you want, but otherwise no worries. We're doing fine. Maybe you'll check it out sometime when some drama happens at Bluesky. The fediverse is not going away any time soon.