Can a CFI endorse a BFR flight review through real-time video including the flight portion?
It seems to me that your question is simply &quot;can an instructor provide flight training from the ground?&quot;, whether it's for a flight review or something else. As far as I can tell, the instructor must be in the aircraft. All emphasis below is mine.
61.1:

Flight training means that training, other than ground training,
received from an authorized instructor in flight in an aircraft.

61.195(g)(1):

(1) A flight instructor must perform all training from in [sic] an
aircraft that complies with the requirements of §91.109 of this
chapter.

The Williams interpretation (2018) talks about instructing from the rear seat (see this somewhat related question) and states that the regulations require the instructor to be seated in a pilot station per 61.195:

Section 61.195 prescribes limitations and qualifications for flight
instructors. As evident from the heading in § 61.195(g), § 61.195(g)
prescribes limitations on the flight instructor's position in an
aircraft and required pilot stations for flight training.
[...]
The regulation would not require two pilot stations for a training flight unless the flight instructor were required to provide flight
training from the one of the pilot stations.

That last statement seems very clear. In any case, the idea of providing flight instruction from the ground doesn't seem realistic, in my opinion. Even with great cameras, will the instructor be able to see your knuckles are white on the yoke from poor trimming technique? How would you do exercises under the hood (if needed)? There are just too many things that would be difficult to do and/or difficult to assess.