I'm using that setup: <setting id="debug.setextraloglevel">128,2048,32768,262144</setting> so ffmpeg is covered. I didn't try with ffmpeg 6.1.1 though.
I tried that sample file attached to 23699 and it works fine for both software codec and hardware acceleration, see the log. As expected, with vaapi enabled it plays very smoothly, while it slightly stutters with software codec.
So I suppose it is something else im my stream which causes these issues.