I think this comment convinced me. Because you’re right, on Reddit there were always offshoot communities that were essentially the same exact thing just of different sizes and run by different people. There’ll probably always be the “most popular” one, and then several offshoots for the same topic but perhaps a better sense of community because it’s hundreds or thousands of users vs millions or tens of millions of users.
Remembering the exact instance and community name combinations will take a little extra effort, but not significantly and subscribing negates that mostly.