I'm very confused about the Pauli exclusion principle. Wikipedia states it as "two identical fermions cannot occupy the same quantum state in a quantum system". I understand this for electrons that for each energy level in an atom there are two possible electrons that may occupy this energy state but with opposite spin numbers.
What about for protons and neutrons?
Protons and neutrons are both fermions, so why in a nucleus can multiple protons and neutrons simultaneously exist. I understand that neutrons and protons are not identical fermions but considering them individually, suppose in a nucleus with X protons, are the energies of individual protons different from one another (and similarly for neutrons in the nucleus)?
Apologies, I'm not very familiar with quantum theory or the maths involved. I super confused about how the exclusion principle works for protons and neutrons. The only explanations I've been able to find consider 2 protons and state that they can have different spin. What happens when we consider more than 2 protons/neutrons?