the climax that is apparently just about finding the right “anti-chord” to banish Maestro?
I think this is the most "magical" episode of the season by a large margin, and as much as this sort of resolution makes sense for that kind of story...you have to really nail the emotional truth of the story to make the anticlimax works. In that sense, I agree that this episode doesn't quite make it there.
And the woefully underdeveloped Lennon/McCartney just happens to wander through the halls of Abbey Road and hit the right note to fill the CGI power bar?
I actually kind of liked that moment, though it would have been nice for the Beatles to be more involved prior to that point.
the silent moment where the Doctor’s sonic cancels out all sound
Definitely the high point, dramatically speaking.
Careful...