Project created on Steam Deck doesn’t output sound

It doesn’t output sound if I create a project on Steam Deck and try playing the recorded audio track from the audio interface or the SinGen synth using virtual keyboard.

The track has audio waves

Looks like connections are missing or lost. Do you use JACK?
In any case: connect master out to your soundcard’s outputs:

and the track’s output to the master-bus using the output selector at the bottom of the track(s). The following screenshot may help:

Changing the routing fixed the project sound