I also had a look at your diagnostic reports, and I don’t know how to say, I’m very confused.
First of all, there is only one real crash report contained, and that is from the audio engine. That crash most likely comes from a case where, as Paul already explained, you had Dorico 2 running before. So that just happened once and is actually not a big problem. But you say that you have frequent crashes of Dorico and that playback is not doing at all.
Well, is it really crashing or is Dorico just hanging, i.e. not responding? From our developer point of view this makes a big difference.
From the logs I can see that Dorico sometimes was waiting for the connection to the audio engine and then the log just stopped. Did you force quit Dorico at those occasions?
When you run into that problem again, please check in the Activity Monitor if you can find a process called VSTAudioEngine in the process list.
Also, what happens when you create a new project from piano template (with HALion Sonic) and add a few arbitrary notes? Does that play back?
We need to find out if your problem is specific to a project or happens in any case.
We really try to help, but it’s going to get difficult and will take time.