Getting neighboring dynamics to stack

is there any way to get this to happen without fiddling in engrave mode?

(Desired on top)

Not really, as far as I can tell. If you flip the hairpin above the stave (in whichever mode) then bring it down below the staff in Engrave mode, it won’t mess up the horizontal spacing.

Or you could add the “espress.” to the hairpin, although I think it would appear below the hairpin rather than above it by default.

I couldn’t find a way of flipping the espress. to the other side of the hairpin. That said, it was the middle of the night and I was playing with a very old version of Dorico…

I don’t think you can - except possibly by using your method of setting its placement “officially” on the other side of the staff then moving it graphically in Engrave mode (*stated without double-checking in Dorico myself)