Perhaps it is the ripping of this verse out of context that has you confused
The problem is that 1 Corinthians 2:9 should never be quoted without including 1 Corinthians 2:10. This is the reason there is a hyphen at the end of 2:9

9 But, as it is written,’What no eye has seen, nor ear heard, nor the heart of man imagined, what God has prepared for those who love him – ‘

So what does verse 10 say?

10 these things God has revealed to us through the Spirit. For the Spirit searches everything, even the depths of God.

Try and read in context next time.