With regards to Unihertz, I'll add on top of what you said, that they are hiding behind ""crowdfunding"" to give non-existent customer support, while devices have already passed Google certifications months ahead (so my guess is that the device is actually already produced when they start the crowdfunding). In my case, the smartphone I ordered never arrived, and I never got any compensation for it, even though
However, hardware-wise, they aren't too bad, so once you managed to receive it, and you flashed a GSI on it, it's a rather acceptable experience. I know someone daily-driving a GSI (I think it's ProtonAOSP?) on Unihertz Jelly 2, and they are happy with it.
In my opinion, Unihertz small phones are fun, but /too/ small. As the article says, target would be 5-5.5" borderless, 4.5" in Jelly2's format, and I couldn't find any model that match. Closest is Xiaomi Qin 2 Pro (I have it, the form factor is really awesome), but it is too thin and thus its battery is abysmal. (If anyone is interested in Xiaomi Qin 2 Pro, yes it can run GSI just fine, but it requires a bit of work - feel free to send me an email for help)