Gold is the best investment by far, here is performance since 1970.

Sadly this investing subreddit don't allow me to post pictures, but I will deliver the point by words.

Since 1970, when the USA set a "temporary pause" to not back the dollar by gold.
Since then gold have gained 15,000% return, sp500 7,500% return, nikkie225 2,600% return.
Gold by far gives the most return.
If you don't want to add the recent bull run, we will go to gold lows in 2015 when it was 1,000$, this will give us roughly 2,900%return from 1970, and SP500 would give us 2,100%, nikkie225 would give us 900%return, gold still wins.

Pro index fund argument is if you add the dividend it would increase SP500 return but I ASSUME gold will still win, so correct me if am wrong in the comments, I couldn't find dividend adjusted numbers.

Pro gold argument is, not all nations fare well, you can look at nikkie225 and other countries, sp500 is the luckiest out of the bunch, but I don't think this have to be the case in the future, you can't just take the luckiest country and say this is the normal return, unlike gold which is more general because it is the most pure form of currency for every nation across all civilizations time IMO.

I would have loved to add China and UK ETF for this comparison but I didn't find one that started from 1970 or before.