Classical Sonata for Auditions in Switzerland

Hello, I've got a question about conservatory audition program. Musikhochschule

It is required to play a full classical Sonata or variation-work, but in a few other schools here just a main sonata movement.

What would you recommend? I have from now about a 1.5 years time.

I'm 17 and the hardest pieces that I played are:

Chopin 3rd Ballade (working on), a good amount of etudes (excluding hard one like Op. 10/2 etc.)

Debussy Feux d'artifice

Prokofjew 3rd Mov. from 2nd Piano Concerto (working on)

Rachmaninow Etude-Tableaux Op.. 33/6 e-flat minor, Op. 39/9 (not finished yet)

I have never played a full length sonata, all movements by classical composer, I'm more interested in contemporary music and 20th century...

So what would you recommend? I kinda like Waldstein but not sure how hard it is. And I don't know about Mozart, because it is really hard to play his music exceptional in an audition.

Thanks for feedback!