This talk at Fosdem 2024 is also interesting & relevant:
Held by an Linaro employee about which functionality of Qualcomm SoCs is already supported by mainline Linux.
In contrast to that, the “SoMainline” GitHub repository covers the additional patches needed to support the peripherial components (PMIC, display, camera etc.) used on a couple of mobile phones, among them a few Sony Xperias.
While the Fosdem talk is impressive, the “SoMainline” repository shows well, that SoC support is the largest, but not the only hardware support necessary.