Starting shairport-sync with exec-node

Maybe someone can help or explain:
I install shairport-sync on a Raspi 5 with Rasbian OS Bookworm. In a terminal from GUI of the Pi5 I can start the shairport-sync program: playing with new audio-system pipe wire on usb with a 7€-USB-3,5"-soundcard from iPhone to headphone is working...YES!
With the old version-Raspi4-and Bullseye I can than tell the systemctl daemon to start shairport at boot as suggested in the GitHub-tutorial of shaiport-sync - not so with the new sound system: because this sound system (pipe wire, pulse audio) needs a logged in user - and the systemctl daemon starts before the user has logged in- and so shairport output goes via alsa into null device ...-> no sound. shairport-sync pulsaudio

So the idea was born to start Shairport-Sync from exec-node after some time. But the simple flow inject->exec-node with the command"shairport-sync" starts only "part of" shairport: I can connect the Airplay-service with a iPhone - but no music is playing!

What is the difference between a bash-command directly on the Raspi and the exec-node in Node Red on the same Raspi...??
Maybe someone of this great forum knows?
Thanks in advance...

Finally I found a solution to start shairport-sync after user login at:
https://github.com/mikebrady/shairport-sync/issues/1749#issuecomment-1778622232
First it didn't work, but I delete "OnlyShowIn=wayfire"
and add a"-sync" at line "name"...
now running.
But the user right management between exec-node and the bash seems unclear to me...