There has been a set of buttons available for a while from a popular aftermarket vendor (https://abstractocean.com/products/s3xy-buttons https://abstractocean.c

There has been a set of buttons available for a while from a popular aftermarket vendor (https://abstractocean.com/products/s3xy-buttons https://abstractocean.com/products/s3xy-buttons) that interface through the OBD2 port. There is a good amount of reverse-engineered information out there on Tesla CAN bus messages (e.g. https://github.com/joshwardell/model3dbc https://github.com/joshwardell/model3dbc). If you have some coding and electronics experience, it'd pretty much be a matter of gluing some libraries together. Probably easier than gluing the physical buttons to the car.