I have the same kind of stutter as you where I just can’t get anything out. Thankfully I have found ways to control it and it’s gotten noticeably better. I’m a drummer and started taking lessons about 4 years ago. Before that, I was terrible at speaking. I would stammer constantly and would avoid speaking as much as possible. But for some reasons it improved after I started drumming. I learned a sort of concept of rhythm, and that really helped. I speak in time now. For example everything is fluid and “in beat sort of”. It sounded kind of alien like when I first started speaking but I’ve controlled it to the point it’s only noticeable if I tell them about this. What I’ve found also helps is counting off from three and tapping on your leg with the count before speaking. It gets my mind off stuttering before I speak. I hope my tips helped but I know it’s different for everyone. Good luck!