I've never been in a Tesla so don't know if this would work, but you might try getting a small convex mirror (often called a "blind spot mirror") like these [1] at Amazon. I linked Amazon for convenience. They should also be easy to find locally at anyplace that has an auto section like Walmart, or auto parts stores like NAPA, O'Reilly, and AutoZone.

[1] https://www.amazon.com/s?k=blind+spot+mirror