Major INDI Library release v1.9.0 bring significant internal changes championed by @pawel-soja to modernize core INDI Library drivers and clients. New drivers for DeepSkyDad Flat Panel & Pegasus devices plus further improvements to PCM8 drivers.
So after hours of debugging and trying to figure out why it wasn't working as it should, I've figured it out. In my case it was about the unit file itself.
On the Odroid C4 running Ubuntu 20.04 I have to slightly change it.