Eternal question. Buy the market now, or wait? Got rid of my individual stock portfolio and decided to get back into ETFs

The idea is either a lump sum investment into World, Small Cap US, S&P500, Nasdaq, and SMH (semiconductor ETF), or waiting out. The cash is parked in overnight ETF for safekeeping.

I am scared of the idea of buying tech at all time high, but not sure how much longer the rally will hold.

Would you invest everything now, or wait out?