In the world of virtual machines, UDP is always the first thing to die. Xen on Amazon, for example, would often (and almost always, if there was any load at all?) silently discard most UDP traffic, and this was true for years. VMWare (back when it was still being actively developed and supported) had fairly atrocious support for UDP as well, and the "atrocious support" level was only if you explicitly enabled it and carefully configured it in the first place. In one VM implementation (15+ years ago, so I can't remember which, but probably VMWare or Xen), we determined that the UDP buffer size was a total of one packet (~1500 bytes). So if you wrote a test that sent or received a burst of more than one packet, only one packet out of the entire burst would have greater than a 0% success rate and the rest were lost.

Back then, I was testing with UDP on EC2 before EC2 was open to the public. I was working with UDP-based server clustering tech (previously used by Amazon, since acquired by Oracle). Still have the scars.

It's been many years, so my guess is that reasonably decent UDP support has slowly crept into EC2 and other common cloud and virtualization environments, and may even be decently supported by now. It needs to be very good to support the transition to HTTP/3 (which coincidentally I'm currently working on).