In principle, you should (should as in “untested” 
) be able to use the “screamer” fork (based on QEMU 7.1.94) from QEMU-based MacOS 9.2.1+ operating systems have no sound, audio not supported - #2 by ethan.gates for other QEMU architectures (e.g., x86(-64)) as well. The same caveats would apply, i.e., you have to enable “WebRTC Audio (Beta)” and “XPRA Video (Experimental)” and specify -audiodev pa,id=pa,server=/emucon/data/sockets/pulse-iosocket as “nativeConfig”.
For a more general solution, the problem is that emulator support is currently hardcoded into eaas-server (for specific versions of emulators as their configuration might change between versions, this is why you are required to manually set -audiodev pa ... via nativeConfig in the example above). We do have plans to decouple the emulator implementation from eaas-server (as presented at iPres last year, though the ideas there are slightly outdated: https://doi.org/10.17605/OSF.IO/XEYR3) but have not implemented this yet due to other priorities.