Any idea? Apple isn't helping me.

I was able to submit it, feedback ID: FB9989352

I tried to submit it as feedback but that also hangs with the message "Preparing" and never actually submits it. I tried multiple computer, browsers, and even different internet connections.

I contacted Apple support, I didn't file it as a bug or feedback. I only have a case number if you want that?

No, in Photoshop. I tried saving it in many different ways. But open to any other suggestions.

Nope

That seemed to speed up typing, but when hitting a return key or deleting a block of text is still super slow. I submitted a bug report ages ago and no progress.