I'm not meaning to be negative at all, but was this for a toy/hobby or for a commercial project?
I find that LLMs do very well on small greenfield toy/hobby projects but basically fall over when brought into commercial projects that often have bespoke requirements and standards (i.e. has to cross compile on qcc, comply with autosar, in-house build system, tons of legacy code laying around maybe maybe not used).
So no shade - I'm just really curious what kind of project you were able get such good results writing ESP32 FW and kernel drivers for :)