I agree wholeheartedly, Sam! A bias is just your favorite member while you stan the whole group, and that's a good thing. I think solo stanning is when the only reason you're into a group is that one member, and imo that's not how stanning should go.
I think of it as like a partner. If you only like the partner, say, because he's into BTS like you are and nothing else, you don't really like him as a person. And the same goes for solo stanning - if you only stan Jimin and not RM, J-Hope, or the others, you don't really like BTS as a group.