Hi, OP here - at the time of my original post my computer had completely totally died on me shortly thereafter (unrelated, it was over 10 years old and it was time for a new machine anyway). That said, I was without a computer or use of Dorico for over a month until I got my new one (MacStudio M2 running Ventura).
It took me awhile to get everything installed and most things are running smoothly, except Dorico 5 is giving me this same exact issue, on a completely new machine and OS and installation!
I followed the steps in this thread using the create dorico diagnostics zip file provided by Ulf, and all the different chmod -rx commands in Terminal, and nothing happens. No zip file appears after any amount of time. I’ve tried it numerous times and ways of syntax, still no luck. Please help, I’d love to get Dorico open again after all this time!