Thanks for the suggestion. I did that, and now the crash report is more cryptic:
Crashed Thread: 0 Dispatch queue: com.apple.main-thread
Exception Type: EXC_CRASH (SIGABRT)
Exception Codes: 0x0000000000000000, 0x0000000000000000
Exception Note: EXC_CORPSE_NOTIFYApplication Specific Information:
abort() calledThread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libsystem_kernel.dylib 0x7ff811eecffe __pthread_kill + 10
1 libsystem_pthread.dylib 0x7ff811f231ff pthread_kill + 263
2 libsystem_c.dylib 0x7ff811e6ed24 abort + 123
3 QtCore 0x10ff02019 0x10fee8000 + 106521
4 QtCore 0x1101c3096 QMessageLogger::fatal(char const*, …) const + 202
5 QtGui 0x1104fde6d QGuiApplicationPrivate::createPlatformIntegration() + 7021
6 QtGui 0x1104fde8b QGuiApplicationPrivate::createEventDispatcher() + 27
7 QtCore 0x1100d26f3 QCoreApplicationPrivate::init() + 1171
8 QtGui 0x1104f8699 QGuiApplicationPrivate::init() + 57
9 QtWidgets 0x10f93cc8a QApplicationPrivate::init() + 26
10 SuperCollider 0x10ee3c1e7 0x10ee34000 + 33255
11 dyld 0x116fb952e start + 462
(I have found and documented a way to work without the full comping process here using only a custom scsynth but it would be good to find what is happening I reckon for other people so if you want I’m happy to continue to try to get it to work)