How do I compress specific frequencies?

I want to quiet down the red areas in the upper half of the spectrogram. Everything that I try also quiets down the blue parts. The spectral editing lets me select horizontal lines, but not vertical or diagonal ones. What do I do?

We are warned against getting too far into the weeds too fast.

What’s the actual job? Depending on what you’re doing, we may have other handy and prepackaged ways to deal with it.