I am making progress and uploaded a new, much more stable version of ClipDeck, that is open for testing: https://github.com/jakobkilian/ClipDeck
You can use one or more Stream Decks (only XL right now). I added scrolling in all 4 directions. There is also a mode that scrolls up/down/right and resets to the default offset (e.g. left border). And there is vertical scrolling or no scrolling. Brightness can be set on the device.
I want to release this Open Source in the end, but maybe for some little money. But I am still undecided. Ask me anything, drop me a line if you have feedback. I am very curious if it works for you.