Just wanted to check in and say that I am also having the same issues and have done throughout all the recent iOS updates, on an iPhone 11 Pro.
Sometimes my phone freezes completely when trying to send a screenshot, sometimes the screenshot edit screen doesn’t appear, but the screenshot will be in my albums, sometimes nothing appears then 5 jump on screen all at once. When I turn my phone on and off, the issues clears for a while, but soon returns.
Bizarrely my fiend with the same phone has never experienced any of this. What is going on here?
Example photo of when it freezes attempting to send a screenshot.