I googled what the easiest piano concerto is since I'm a beginner. I got Schumann in a minor. Then I went to IMSLP, and it gave me the “easiest piano concerto.” :
Schumann Concerto Piano Imslp - Colaboratory
Piano Concerto in A minor, op. 54 Cello Sheet Music by Robert Schumann | nkoda | Check It Out in the nkoda App
Piano Concerto - Op. 54 - Robert Schumann - Partitions - Cantorion, partitions gratuites et des annonces de concerts