Hello,
I do have the same issue on a Surface Laptop 3 AMD Ryzen 5 bought last year on release date.
One thing to notice:
Back on the release date, no issue. It only started to happen after about 1 month of daily use of the laptop.
A month ago, I reset the PC. Works perfectly! Until about a month ago... It happens again... I think it might be following a driver update from September 2nd, but I can be wrong.
Additional note:
It happens with and without a Bluetooth headset (Sony mx 1000xm2). It happens in MS Edge (Chromium), Windows Movie Player and Movie & TV app.
Pausing the movie and pressing Play again sync up the image and sound again, but it progressively becomes out of sync again.
It happens on both, Surface Laptop monitor, and external monitor. Both are on 60Hz.