Today I discovered Pianoteq. With the help of Pianoteq_RaspberryPi3_v3.pdf I configured a Raspberry Pi 3 which was being used for HifiBerry and Spotify. With a new SD card I got it working till a certain point.

Using dtoverlay=hifiberry-digi in config.txt the DAC is not shown using the aplay-l command.
Using dtoverlay=hifiberry-dac do gives a result: card 1: sndrpihifiberry [snd_rpi_hifiberry_dac], device 0: HifiBerry DAC HiFi pcm5102a-hifi-0 [HifiBerry DAC HiFi pcm5102a-hifi-0].

PIanoteq starts up and show the DAC, however without sound. Any suggestions?

My final goal would be to purchase Pianoteq 8 and combine it with a studiologic sl73 studio.