Increasing your blood magic skill[valheim.fandom.com] is the answer to most of the "problems".

Skeletts are amazing because they act as a force multiplier together with your own attacks, thanks to staggering effects. You're not a minion master. You are not a blood mage. You're a viking warrior with skeletons and barrier. If you're relying only on skeletts for damage, you're playing the game wrong.

We can't yet be certain what the final limit for them will be.