So Mike, this was easy; your project had 1,151,529 envelope controlpoints. You were lucky. The last project I saw had 10 times as many. Anyway, I removed them easily with my AudacityRescue program which I have posted about earlier on the forum, see: https://forum.audacityteam.org/t/3-0-3-experiencing-extreme-slowdown-and-is-not-responding/62439/18 I don’t know how they got there. If you have any clues, please share - I suspect it has something to do with many punch or cut and paste operations. Do you mind if I retain your project for futher research?
Your “rescued” project has been posted. Your project should be back to its speedy self. 
I have sent you a link. In the future you can download the rescue program and run it yourself, or I will be happy to assist you again, if you prefer.