Japan makes incredible bidet toilets that got some traction during the pandemic. The jokes write themselves but a smart toilet that had health tracking features liked to the rest of the Apple fitness eco-system could be interesting.

The security camera, door lock, and thermostat space has room for improvement. The annual subscription model for cameras combined with their privacy gaps opens a space for Apple. My car unlocks when I walk up to it. Shouldn't my house do the same?

Kitchen appliances have gone done in quality to the point that they are replaced every few years when the linear motors fail. I don't know if there is enough margin for Apple but knowing what food is cycling through the kitchen would be another interesting health input.

3D printer, laser cutter, replicator machine that manufactures physical goods in your house.

Automatic pool/hot tub system that keeps chemical levels balanced and orders supplies as needed.

Urban gardening pods that allow anyone to grow healthy food at home.