I believe I'm having the same issue here - I have a USB DAC (Dragonfly Black) that I plug my speakers into via a 3.5mm jack. I'm on the latest Windows 11 24H2 update too; all drivers up to date; USB suspend is disabled.
Essentially, the USB device goes to sleep if there is no audio playing. When I try to play something that emits sound (youtube video, MP3s, etc) there is a delay of 2-5 seconds before the audio starts.
If I plug my 3.5mm jack directly into my motherboard (removing the USB DAC) this issue goes away. Trouble is that my motherboard audio is rubbish.
Not sure if this is the same issue everyone else is experiencing but it is annoying af.
Any idea what I can try to fix this issue since MS doesn't seem capable of fixing it themselves.