I just had a Déjà vu reading about the Logitech K780 and Pebble mouse. I used the same exact setup for my iPad 4th Gen before upgrading to the M1 iPad Air. It was a beautiful setup and I would probably still go with that setup if the Magic Keyboard hadn't spoiled me so much with it's portability.
Glad to read about your iPad and Mac setup. Looks super efficient. I am thinking of setting up a desktop soon myself and your mention of the M4 Mac Mini might seal the deal for me here. Thanks for reading and sharing your view, Lloyd!