I feel your pain. I'm also struggling a lot when presenting but recently zoom classes got me to experiment little bit. I found myself doing best when totally ignoring the presence of listeners. During the online workshops I hide everyone's webcams, share my screen and talk through the problems/assignments for myself, with my third person self as a recipient. It's a bit weird feeling but I find that everyone else has no problems following my thoughts that way and it takes a lot of pressure off my shoulders/mouth 😂 Maybe this can also be done while presenting in person...