The only practical solution to learning music theory is to have it to the music that you are playing, otherwise, it's an abstraction or a math construct which may or may not be translated into musical auditory use.

There are many music theorists who know the mechanics but find it difficult to integrate it into their playing. As a music teacher for over Sixty-five years, students have come to me with a knowledge of key signatures, cycle of sevenths (fourths and fifths), basic chord construction and I've had to show them how to use what they know.

I teach a Tuesday evening jazz guitar class and we grapple with chord construction,
transposition, linear and vertical approaches to improvisation and memorizing of tunes and chord progressions.

As stated above, the ears are often more important than the theory which comes afterward.

Music theory is not rocket science but the student must be shown how to use it.

My goal is sometime to be able to crack the code of the Schillinger system of musical math but I need someone to show me how to do it, this, after over my seventy years as a working musician. Moral: You can never know enough.