I think you are missing a step in the proof. That could still be a composite, see here: https://newbedev.com/understanding-euclid-s-proof-that-the-number-of-pri

I think you are missing a step in the proof. That could still be a composite, see here: https://newbedev.com/understanding-euclid-s-proof-that-the-number-of-primes-is-infinite https://newbedev.com/understanding-euclid-s-proof-that-the-n...