I have no answer to your request for reading material on EQ, because I've not found any text that does a good job of it.
The reason for that is it's a surprisingly complex topic. It feels as though it should be simple, but that turns out not to be the case. Sure, there are a few widely-accepted practices, such as avoiding mud-range build-up and rolling off the low bass. But for every rule of thumb there are a dozen exceptions or "it depends" and special-case scenarios. Turns out, every mix is a little different.
Your best bet is the long road: acquiring a fundamental understanding of frequency, harmonics, summing, masking, and the limits of human auditory perception. Example: if you have a muddy mix, why can't you just throw an EQ onto the master bus and attenuate the lower mids? Everybody tries that, and everybody figures out that it doesn't work. It doesn't work because your ears don't work that way, but you'd probably not come to that conclusion by following cookbook approaches to EQ and mixing.
If I was starting over from scratch, but somehow knew in advance what I'd need, I'd begin by studying the physics of sound, the human auditory system and psychoacoustics. You won't find these topics in the "Music" section, but they are the foundation of the mixing arts.
Another unexpected but beneficial tangent is the study of perceptual encoding, because it leverages the limitations of human hearing to reduce file sizes by eliminating things you can't hear.
Knowing what you can't hear and why is a big deal in mixing. Acoustics, there's another ancillary topic that also ties in neatly, because it deals with how humans interact with their sonic environment and how they sense sound. Another less-than-fun exercise involves ear training, e.g. learning to identify frequencies by ear.
These fields of study may seem tangential to mixing, but are in fact fundamental to it. A great mixer needn't have necessarily read the textbooks, as many great mixers have figured this stuff out through experience. But either way, it's stuff you have to eventually figure out, so instead of waiting 20 years why not take a shortcut?
Here are some titles that won't teach you how to EQ, but
will make you a better mixer:
Mixing Audio by Roey Izhaki
On the Sensations of Tone by Hermann Helmholtz
Sound Reproduction: The Acoustics and Psychoacoustics of Loudspeakers and Rooms by Floyd Toole
Master Handbook of Acoustics by F. Alton Everest
Digital Audio Explained for the Audio Engineer by Nika Aldrich
Zen and the Art of Mixing by Mixerman
This is Your Brain on Music: The Science of a Human Obsession by Daniel J. Levitin