Got the same dropout problem here using Windows 10 Pro 21H2 with 3 different USB audio interfaces. Dropout is every 3 seconds periodically.
After research in internet that seems to be a known problem after some windows updates and microsoft says there is no way to step back.
Don’t know if the onboard audio has the same problem.
For me the workaround was to use the HDMI audio going into the monitor and use the headphones plug to route to the powered speakers. Driver is Asio4All.