The reg 61.56 is pretty direct.
(c) Except as provided in paragraphs (d), (e), and (g) of this section, no person may act as pilot in command of an aircraft unless, since the beginning of the 24th calendar month before the month in which that pilot acts as pilot in command, that person has—
(1) Accomplished a flight review given in an aircraft for which that pilot is rated by an authorized instructor; and
(2) A logbook endorsed from an authorized instructor who gave the review certifying that the person has satisfactorily completed the review.
The (d) (e) and (g) exceptions are if you passed a checkride you’re good or you renewed your CFI you don’t have to do the one hour of ground training or if you’re a student pilot and signed off for solo. So you have to do something in an aircraft for it to count as a flight review. I recall that the FAA guidance for an examiner noted that the examiner should point out to the recipient of a based on certificate holder that they needed to complete a flight review prior to exercising the privileges of that certificate but I can’t find that guidance anymore.