@DANmode and @storywatch both called out good paths to explore.

I daily drive a monochrome PDA as my core "smart" device. The overall UX is excellent for what it needs to do. Despite color PDAs being widely available, I've found I prefer the B&W UI quite a bit more.

A common refrain from me is that digital calendar UX peaked somewhere around 1999-2000 with PalmOS 3.5 (particularly on later Handspring Visors). I've also written most of a little weather app using native UI elements for them.

Additionally, the Modos folks seem to be on to something with high refresh rate eink. It's quite smooth in practice and is almost uncannily like a normal LED screen with an e-ink look.

Early Macs also had pretty opinionated HIGs, as you said.

Feel free to reach out if you want to chat further. Frankly a lot of the design principles are the same as broader graphic, type, and UI design best practices--they just aren't often followed by anything modern. Something that's always stuck with me from a professor was that a good logo must pass the "fax machine test". Seems quite applicable to this day in an eink context! :)

Link to some PalmOS UI guidelines: https://cs.uml.edu/~fredm/courses/91.308-spr05/files/palmdoc...

^ These are a bit newer and include color. The UI elements originated in mono and were still backwards comptaible with mono devices, so I find the addition of the blue to be distracting rather than additive, but YMMV. Either way they also look much better on a proper 160x160 LCD vs a PDF!