First testing confirmed that UDP Acceleration works when connecting to a CG-NATed server via AzureRelay.
50mbit link, 2kkm away from server - https://prnt.sc/nbnJ2zawe09-
While testing on a couple of different servers I found another issue, but with UDP NAT-T type of connection. When connecting to server via *.softether.net domain the download speed is abnormally low and "UDP Supported NO" is displayed on Server side. But connection to same server via azure lacks this problem

This issue is reproducible on previous stable version of the app too.
Client: AzureRelay vs NAT-T - https://prnt.sc/Pr9vqcGHQtUB
Server: VPNClient Pro vs Native Client - https://prnt.sc/Eu0rstoP4BHb