"Don't tell me what you think, tell me what you have in your portfolio." Nassim Nicholas Taleb, Skin in the Game

If you're convinced Tesla is vastly overpriced, you should prove it by shorting the stock or buying put options.

Betting against Elon Musk has been a terrible move up until now, but if you really think the stock is overvalued, you're probably better off simply not owning it. If you're still concerned about its inclusion in the S&P 500, you can buy an S&P 500 index fund and short just enough Tesla stock to exclude it, or buy a different index fund that doesn't include it.