[nrp]

It's an interesting challenge, but MIPI DSI is sort of the right interface for small size displays too high resolution to drive with SPI. There are a range of Cortex-M4 and M7 MCUs that have DSI output (e.g. https://wiki.st.com/stm32mpu/wiki/DSI_internal_peripheral). The solution is probably just better documentation for the panels and their DDICs.

[cxcorp]

Oh wow, I didn't even know ST had a wiki! I wonder if they also have a section on the STM8 family?