Not all cuttings like humidity!

Normally when you want to root cuttings you put a clear dome over the cuttings to keep high humidity. The second rule is that you only keep the plug moist.

The above method is true for most cuttings but there are exceptions. Some sets roots best when you just stick them in a glass of water. Some, like geranium, will not root if you put them in high humidity.
Succulents typically needs to rest 24 hours after cutting them and before sticking them in the plugs or in a glass of water.

So before you try to root a new kind of cutting ask your garden center for advice or search the internet. As much as we would like to have all answer for you here, we don’t know all plants that exist.