Looking at historical S&P 500 to Gold ratio, stocks are definitely more expensive but nowhere near dotcom frenzy. Either we see market correction or gold is undervalued and will catch up. In that case there might be no stock market crash.
Gold is not a suitable comparison to stocks - it gets brought up on here all the time. Gold is not uncorrelated to the market. Gold is not a store of value. Gold is a speculative investment with a great marketing team.
Gold has two things going for it: there's a baseline of "real" value underpinning it (not just industrial use, but lots of fast-growing Asian countries relying on it for dowries etc), and historically gold holds up quite well when everything else is doing badly. However, it's also fundamentally unproductive (no dividends, no real capital growth), so it's going to be a losing bet most of the time.
https://www.macrotrends.net/1437/sp500-to-gold-ratio-chart