Someone had to say this lol
Welcome to the #real talk
As I said, group fans aren't under any obligation to support or like all solo projects. They are primarily there for group content, they fell in love with a group and they like groups music.
When members decide to branch out in solo career at most they can expect from these type of fans is visibility and that they will stick around for their solo music only if they like it. The moment members start solo work it is like debuting all over again, they have to build their own following.
This also works other way around, although I think that akgaes have more reason to check out group projects simply because their fav appears in it, they are also not obligated to like or support it.
Rant over!