thank you all! I do have a gear selector from a polestar 2, as well as its harness, but I'd need to figure out its CAN messages as well as its pinouts and I haven't had luck with that.

@mattsawesomestuff, I remember watching that video and I had considered that option early on, but wanted ...

Cool! Order placed! I have been thinking of converting a Volvo 850 for years and your book will be a huge step forward.