2 series that I really enjoyed but don't see recommended a whole lot are:

The Whispering Crystal's. First book titled Unnatural Laws. This one is about groups of people transported to a different dimension where they have to make their way through a gauntlet style arena. The fifth book was released recently but the series is not complete yet.

Crystal Shards Online. First book titled Dodge Tank. I get the impression that this type isn't super popular due to being a ready player one type setting where everyone spends all their time in a vr world but the premise of this one actually makes sense to me. Its a post apocalypse world and the survivors are facing annihilation and the mc gets sucked in to saving it.