That's the tricky part. One the one hand, most of us ended up here bc of Bitcoin, so that's often going to be the largest common interest. On the other hand, this format won't ever gain adoption if we limit it to just Bitcoin stuff.
@koob has said before that he doesn't want to add more subs until there is a substantial amount of posts on other topics. But perhaps we can merely get a thriving "other" category going.
Either way, Bitcoin posts will probably get 95% of the sats for a while.