Help me appreciate Rachmaninoff's solo piano music

For context - I studied at two top conservatories, and had a career as a concert pianist before burning out and transitioning into a different field of music. I have played his 3rd Piano Concerto, which is one of my all-time favorite pieces of music. I love the lyricism, drama, soaring melodies, and lush harmonies of the Piano Concerti and the Rhapsody.

However, no matter how hard I try to get into his solo piano music, it just... falls a bit flat? I don't dislike it. There are some beautiful and thrilling pieces. But I feel like a lot of it is missing something? They just do not seem to have the same drama and beautiful melodic material of his bigger works.

Obviously a piano concerto is always going to feel more elevated in a way to solo piano repertoire. But I don't feel this way about Beethoven, Chopin, Liszt, Prokofiev, or many of the other composers that wrote for both.

I would love to find a way to appreciate his solo works more. I have played so much of the standard repertoire, and this is one of the biggest areas I have skipped over. Not sure exactly what I'm asking here, but would love to hear what others most appreciate about his solo piano works