Not ignoring recent developments but something also to note. A phone repair store in Europe has listings for Pixel phone display assemblies that are labled as non OEM LCD/TFT and not OLED. Assuming its not simply mislabeled it also could be of interest. Unfortunately the most recent device they support is the 6a.
Third-party LCD/TFT displays do exist for several models of iPhone but I was under the impression such a solution only existed because of the economy of scale.