Miele has home dishwashers that do this now. But like all things consumer, it's a proprietary system that's designed to keep you locked into a subscription relationship with the company.

I have one of these. The detergent gizmo is a hard plastic shell with an interesting shape, powdered detergent inside, and a plastic film cover that looks like it’s heat-sealed on. It contains no electronics whatsoever. You can refill it, and the only limitation is that it’s kind of awkward to open, fill, and re-seal. The easiest way IMO is to cut a large flap in the hard plastic on the sides, then tape it down after refilling. It works fine.

Also, the Miele powdered detergent, in my personal opinion, sucks. And it leaves some residue behind. Yuck.

True for their dishwashers. But to their credit, Miele's washing machines actually come with two additional cassettes that you can fill with your (liquid) detergent of choice. You don't have to use Miele's proprietary ones.

PowerDisk? As long as you load salt and rinse aid, it works like a charm. As you said, if you want to save a bit of money, you can 3D print a replacement. But they last long enough that I don’t mind the cost.