@12many I think you really have two options as workaround -
1. you can add a track to your Qobuz playlist in the Qobuz app
2. you can add your Qobuz playlist to the Aurender library in the Conductor app then add tracks to it there. However in this case it becomes your Aurender playlist and anything you add/remove won’t be reflected in the Qobuz playlist.
I don’t think it’s a deal breaker…at least for me it isn’t.