Hi Martin, I am pretty sure the dynamics are right for the piece. I'll go back and take a listen to see if I really want to change anything.
There are crescendos & decrescendos, I have no idea why you're not hearing them. The movement has a dynamic range of 8.03 dB, which is, I admit, a bit lower than many of my symphonic movements. When I listen to it at a moderately low level, it sounds fine but if i crank it up too loud, it does seem a little flat dynamically. When I master the entire symphony I'll mix this movement at a lower amplitude.
The lack of dynamics in the score has nothing to do with the recording, which contains all the dynamics in the MIDI sequence. I don't put dynamics in the score (nobody wrote out dynamics until the 19th century) because there are no players. Same with string bowings and wind/brass breathing marks. If there were players I'd put them in. I know how to do that. But for digitally produced music they're redundant.
I wrote a brief article about why I don't put these marks in the score, which irritates a lot of composers who write for live players, but I am not concerned with that tradition:
https://www.jerrygerber.com/markings.htm
Here's the waveform, you can see it has dynamic range: