Assuming your smart TV is android, project ivy is my favorite.

Fantastic movie. I went in without knowing anything other than “People said it was good”, and I was blown away.

This post made me try again to find a solution, and maybe a USB extension cord with a on/off switch could work. It’s not automated but would be more convenient than removing the dongle each time. I’m thinking something like this

I have this exact same problem, but with a Chevy bolt. Some cars USB ports are “always on” and some aren’t. Might be worth trying different ones and see if there’s a port that doesn’t power on randomly. This didn’t work on my car, but it’s a common solution I came across when I was trying to figure it out. For now, I’ve just reverted back to wired AA.