Hi,
I will look into the propagated inputs question. Indeed looking at the documentation python does not belong there.
Your example works at a foreign distro using guix (Fedora) with jack, which is where I've tested the declaration. On Guix system it seems to work when using the PipeWire Home Service, but I can't get it to work with the standalone jack2 just yet. So that's something I've got to look into as well.
It wasn't my intention to submit a poorly working patch, sorry. Somewhere next week probably I will compose a new patch revision.
-- Kind regards,
Rick Huijzer