Yes, phones delay video playback so it matches the reported latency of the audio device. This works via networked audio protocols as well, at least on Apple devices in my experience.

1 frame at 30fps lasts 33.33 ms. I work as a freelance rerecording mixer and can assure you that a shift of one frame can definitly be noticible.

However there are some people who are more sensitive to this than others.

50ms would be two frames at 25fps, which is already quite much indeed. Anything beyond that is just a crime against anybody who worked hard to sync sound and image.

This can be easily seen in action when playing audio over AirPlay where the latency is ~2 seconds. When you press Play the video waits for a moment to compensate for the audio delay and only starts after the two-second delay to sync with audio.

The popular type is from Qualcomm called AptX Low Latency (not the same as 'lossless' AptX HD versions) and you need it on both sides xmt/receive. I have never seen this supported natively before so I got them as a pair of headphone jack to BT dongle adapters. Video works fine on Hotel TVs which was my normal useage.

A normal old school ISM band headphone with transmitter base is better for TV but the dongles travel better.

That is a very good point. I have no idea as I dont use it to watch video. Would not be surprised to see if that was the case.