I looked into one such company, Teracube, but they’re low-spec $200 phones, which doesn’t bode well for longevity. They also use Mediatek SoCs, which also doesn’t bode well for longevity; as you may know, Qualcomm recently pledged to provide three years of OS updates and four years of security updates. It would be better if they had open-source firmware, but at least it’s something.