I think you struggled in that first video with fh drop shot because you attempted it more as a bunt than a stroke. I think good repeatable slices and the drop shots, including variation if that is a goal ... is from strokes with rh speed and follow through.
A couple of thoughts, and context:
I think one of the first things I would decide which both you and
@S&V-not_dead_yet mentioned is 1) just an occasional shot ... or 2) regular part of your point construction.
I am in the #2 camp ... have been seen I started playing singles tournaments in my 20s. I had success hitting to targets making opponents hit on the move/run ... and my 1hbh drop shot almost always cc toward the alley was just another available target during a point. It didn't have anything to do with a goal of keeping them closer to the baseline. I seldom use the fh drop shot ... no real reason because I can hit it ... just wasn't part of my pattern.
So in my case using the bh drop shot regularly in point construction and not a couple of times a set, "least UE and good enough" came into play. Hypothetically say I can hit 9/10 bounced twice before service line lower flight drop shots (not to be confused with no arch ... all drop shots need some air). Also assume that is working for me ... winning points moving opponent around. Now assume I can hit a nice high barely over the net with good backspin just over the net ... but I either hit to deep or don't clear the net 4 out of 10. That is no big deal if it's one of your twice a set "keeping them honest" drop shots, but a very big deal if it shows up as high UE in your games and set. My drop shots was such an automatic thing I never thought about it for decades until ttw. I read some comments here ... noted the flashy Fed drop shot ... and tried it with the ball machine. First thought was that was fun ... I can hit this ... did you squirrels see how tight that stayed to the net with all that height and backspin. The problem was just enough variation in depth ... some would have been short of the net, and others just a little to deep allowing the opponent to get there in time for easy shot. Even on my worse lower flight drop shot ... they are almost always hitting a ball very near the court surface.
On disguise ... my opinion that is rated way too high in rec tennis ... particularly when we get to senior tennis. In fairness, I hit every bh (1hbh drive, 1hbh slice, 1hbh drive, 2hbh drive) with a continental ... so I never faced the grip change issue. I also only hit the bh drop shot with a game built around A LOT of 1hbh slice drives ... so the disguise pretty much was built in. When I hit an occasional fh drop shot ... I just prep with racquet high (like S&V @6:28 in his first video above) ... and just hold until last second and hit drop shot.
IMO ... including the entire court as a target area, not just side to side, but front to back is always good in rec tennis ... but WAY GOOD in older guys tennis.