I'm looking at https://beeline.co/pages/beeline-cycling for example, but it isn't clear what display they're using, it looks like regular LCD, not even anti-glare? What's nice with e-Ink, is that it's highly visible even in strong sunlight (extra so when they've focused on anti-glare), while LCD even with anti-glare can be difficult to see.
I've been looking for an e-ink maps/GPS device for years. I feel like turn-by-turn would be a waste of the e-ink, but more like, topo maps that I can use with a compass, and just power the device on for a moment whenever I want a new map tile.
But none of the e-ink devices I've found have an internal GPS chip, and I haven't dug deep enough to find if any have an internal UART or i2c pins to which I could attach one. (Nor do I have any clue how to make the OS see it after I do that.)
It looks like this is just using BlueNMEA to inhale GPS sentences from an external device, which is.... something, I guess.
My rec sailing team uses an e-ink chart plotter. I like it more than anything else I've used for that purpose, it really is a great fit. Unfortunately they're like $800 and I have no idea if it could be adapted to a general purpose gps. I have long suspected it just runs android but never really looked into it and don't know how much that would help anyway. https://www.maptattoo.com