I went ugly on this: BootCamp + licensed Windows 10.
Here's my step by step and the game works perfectly on a 16" MacBook Pro (2019) with Catalina:
- Install BootCamp and reboot when directed
- Install fresh Windows 10 through BootCamp interface
- Boot into Windows 10. (I purchased a license from Microsoft)
- Download DDO and play it daily. No issues to speak of other than headset microphone works via USB but not headphone jack. Probably a driver issue, but I haven't spent time looking.
That's it - this is a Windows game and I surrender to that fact.