NVENC is a hardware (ie CPU) offload ... if you are using a cloud VM, just get more CPU if desired/required.
Assuming Chrome browser... have you looked into
https://support.google.com/chrome/a/answer/9303118?hl=en Chrome hardware accel in a VM?
you may have to go beyond defaults to enable H/W accel for a browser in non-standard environment (ie VM), and understand the CPU impact.
On Azure (or any other cloud provider), the issue you are likely running into, is that their business model depends on running as many VMs on a server as possible. You on the other hand are doing something (OBS / video compositing) that is latency and jitter sensitive (ie you most want consistent performance). These are opposing requirements/expectations. There are VM options (at higher cost) that provide higher performance, including minimums (guarantees).. the specifics of these options (and H/W GPU available) are cloud provider specific.
As a recovering VCP, I can get near hardware performance out of a VM... but it does take knowledge/expertise, and there are certain scenarios that will always be a challenge. Note this means bare-metal hypervisor (ie ESX or similar) not a Host OS with Guest OS in a VM. Virtualization itself entails some overhead. Data traffic traversing the public Internet (especially through Public Peering points) will rarely be that consistent in terms of latency/jitter... which is why streaming video providers have buffers built into their playbook apps/devices
So.. if you are trying to run OBS.ninja over open Internet, to a VM somewhere not specifically optimized for performance, and then streaming that back out over the Internet.... and having audio / video issues .... I'd say "not unexpected"
The audio cutting out isn't an OBS issue most likely, but rather your Virtual PC setup [are you talking the old MS product .. which sucked / atrocious I/O performance.. or Parallels on a Mac?] As noted above regarding virtualization overhead, a full Host OS means LOTS of overhead usually. And translating from Windows OS to MacOS would mean even more overhead.
You mention looking for a different solution, but without knowing what you are trying to accomplish, and your requirements, basically impossible to recommend anything. I could imagine some OBS configs that would work fine as a Public Cloud VM, and plenty that I'd never expect to work. so like so many things, especially sophisticated technology... it depends..