The point as discussed before is that your protocol does not have any start nor stop.
Seems you use it in continuous mode and not in a mode where you ping it to get data. If you were to miss one byte only for whatever reason then you’ll need some robust code to re-sync…
I would keep it easy at the beginning at try with the pulse approach (send a pulse, read the 6 bytes and do something with that, then start again) to have the upper hand on the communication