sections of strictly increasing or decreasing vertical/horizontal ratios

That’s correct but I don’t think there is any place where this rule has been broken except for the ㇓ section (no progression of ratios on a convex curve allows for 1:1 between long stretches of 2:1 and 1:0). And at this resolution, in-between ratios like 2:3 (alternating 1:2, 1:1) are viable, dare I say necessary? It’s a kind of dithering, a technique well-known among colors but less so among shapes. Sometimes you need a slope between the two…

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⣿⣶⣤⣀  
⣿⣿⣿⣿⣿⣶⣤⣀  
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣶⣤⣀  
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣦⡀  
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣦⡀  
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣦⡀  
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣦⡀  
⣿⣷⣶⣤⣀  
⣿⣿⣿⣿⣿⣿⣶⣤⡀
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣷⣄⡀  
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣷⣄⡀  
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣦⡀  
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣦⡀  
⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣿⣦⡀  

The right side could use some 1:3 bits like on the left and shorter 1:0 (orthogonal) and 1:1 (diagonal) sections but this is still plausible.

the back of the dimple on the apple seems a bit too open (?)

Yes. The way I would say it is that the part behind the stem ends too sharply (extend the ⠗ pink part’s tip by 1-2 px to the right)