In Google Maps (where you can open a route from ABPR), when you share to your Tesla, it does use the specific route. I've tested this with a simple, single destination where there were a couple of alternatives, and the Tesla navigation used the spefifically shared route (vs. plotting its own from just the destination).
I'll swear at some point I shared a route with a waypoint and it worked, but that doesn't seem to be the case at the moment (just tested it again, additional waypoints cause the sharing to error out).