+1 for adding Loupedeck support to PL.
Unfortunately PL has always been very poor with scripting capabilities. On Mac it never had support for AppleScript and no surprise it doesn’t support Apple Shortcuts nowadays.
A couple of years ago I’ve programmed an AppleScript suit named APHub to be able to still use my beloved Aperture for DAM but make all advanced photo edits in newer apps like Photolabs or Capture One while preserving all edits inside the Aperture database. While it was easy to interface with Capture One via AppleScript, I’ve had to use GUI scripting with Photolabs to get it working with limited functionality.
Interestingly you can use the mousewheel to adjust values in PL by mousing over the slider and holding the cmd key. PL detects the slider under the mouse cursor and changes the value of the slider.
So the logic to change a slider with a wheel (or knob in case of Loupedeck) is already there but there is no interface to trigger that logic from outside PL.
If DXO would implement the hooks to trigger that logic from outside, Loupedeck or PL users could programm a plugin to make the Loupedeck knobs work in PL.