yeah, index funds are pretty good investments, but boring. I'd not just buy one, though. Diversification is important. Maybe put equal amounts into the following:
US Growth, US Value, US MidCap, US SmallCap, International Developed Markets, International Emerging Markets, and if you want US Real Estate.
Although, at the current time, I'd hold off on MidCap & SmallCap until the market settles out a bit more.

Vanguard and/or iShares are pretty low cost ETFs.

Rebalance annually if/as needed. Continue to buy as frequently as you can (and can afford). This will cost-average your positions.

Once you have a core portfolio established, then you can look at individual stocks/crypto/etc.