@Noideaforanae - As far as the 64 bit question, is StellarMate actually running on a 64 bit OS? I'm using a 32 bit OS (Raspberry Pi OS / Raspbian) since I didn't see an improvement when I tried 64 bit Ubuntu Mate. Long story short, PTP mode should work on the Rpi4, if you're using a 32 bit OS.
However, if you are in fact using a 64bit OS, that would rule out PTP mode removal as being a possible solution to your car charger problem, since the 64bit version of the driver already builds without it.
(I have debated removing PTP mode support to make things less confusing. I decided against that path originally because I wanted to provide the maximum possible support. But as more people provide feedback, if the possible scenarios in which PTP mode could be useful keeps dwindling, perhaps that is a decision to revisit. I could, after all, make a separate driver that supported PTP mode available to those who wanted to compile it themselves).