the issue is not pipewire related but pc related. closing.
It's a lot of time that I noticed this issue, I'm reporting only now. If I watch a youtube video (both with Firefox and Chrome) I notice the video a bit more slow then the audio. It does not happen if I play an offline video. I notice this issue on Youtube and not other online platforms (but I mainly use Youtube)
UPDATE: issue is not pipewire related but pc related because it happens also under LinuxMint and Windows