That's was a good lead, thank you!
I couldn't solve it either way, but we'll see if it was addressed in MXL Sigma.
After tinkering around with wine versions and configurations I was able to get MXL Launcher working on wine.
Previously I had all sorts of exceptions, presumably because Electron (framework for building Web based desktop applications) had some incompativility problems with how wine uses hard drive and mounts devices, thinking that Z: (where root is mounted) is actually a network device.
Having PlugY installed or changing D2 installation path in settings seem to throw "ENOTSUP: operation not supported on socket".
Currently I have upgraded to wine-staging (wine-4.0-rc5 (Staging)) and it solved all those exceptions.
Except, obviously, "failed to retrieve process" error.
Just a few days left and I'll start trying to make MXL Sigma work.
If I am successful I sure would love to write an installation guide for us unlucky Mac users.