Is it possible to extend the settings in the backend to enable also macOS with a running VB environment to receive work units ?

You should be able to receive work units just like volunteers running Windows or Linux. We currently don't have any to ship; we turned on our new WU creation pipeline and ran into resource limits on another server, one that is packaging nanoHUB jobs for BOINC. That should be resolved shortly, and you will hopefully get some WUs soon.

Also, I believe there are some issues with MacOS and the BOINC client. I have two identical iMacs at the same OS level, same version of BOINC and same version of VirtualBox. One does tons of jobs. The other either says no work available for this type of system, or if it does get work... it immediately comes up with "computational error". I've read on other message boards about Mac users having this problem with other projects too, but I haven't done much further digging than that.