If someone can direct me to where this subject has been addressed, thank you.
When a Dorico score is played from the transport control, dynamics within the score do not replay. For example, there is no difference between how loud a voice sounds whether it is marked p or f.
Similarly, crescendos do not execute in playback.
How does one set up the play mode to solve this problem?
If you are using Dorico default sounds, just re-apply a Playback Template (Go to Play>Playback Templates… choose Auto and hit Apply and Close. This will reload all the sounds and apply the correct expression maps.
If this does not work, upload the file (just a few bars with dynamics are needed) and someone will be able help.