The other issue is that none of the SoCs on the market with open source drivers available are remotely competitive in performance with today's Qualcomm/Exynos/K

The other issue is that none of the SoCs on the market with open source drivers available are remotely competitive in performance with today's Qualcomm/Exynos/Kirin. The Pinephone and Librem 5 are both using chips that are competitive with low end Snapdragons from 5 years ago. I think the RK3399 paired with an external modem is about as good as you can do today without needing blobs, and while it performs a whole lot better than the current Pinephone/Librem 5 it is still quite far behind today's SoCs. In most cases the open source drivers for these mobile SoCs are reverse engineered rather than released by the vendor, which is why they typically only exist for chips that are at least a few years old.