https://www.tivo.com/products/stream-4k
This just launched today for $50 early pricing. It's Android TV on a dongle with Dolby Vision support.
As far as I understand it's the regular Android TV home screen, what you see in the product page is the TiVo app (launched by TiVo button on remote)
https://explore.tivo.com/how-to/stream-4k/remote
I've ordered 2 for out TVs, mostly because I love the TiVo peanut remote.. which also has a few buttons most streaming remotes omit like input, live tv, guide, etc.
I believe it has the Amlogic S905Y2 chip (same as Google's dev device ADT-3?). There's no ethernet port, hopefully that can be remedied with a USB adapter.
That's all I've got, just thought I'd share in case anyone else finds it interesting.