The Lynx generators and readers are pretty good.
They were quite late on the scene in the 90s, but from all accounts they do the job well.
Video sync reference is mostly of importance when generating new code (locked to the overall video system timing).
The slave playback speed will either be internally crystal locked, or tied to an external reference (several different types (tone, video, etc)), or in the case of a timecode locked deck, the LTC reader will compare the source time to the playback time - and generate a ‘difference’ signal that is used to accelerate or slowdown 5be ‘slave’ transport.
Continuous lock will keep correcting (undesirable with audio = wow), so these systems usually achieve ‘sync’ then release the capstan override.