Conversation

Every element and isotope is radioactive if you wait long enough, even iron the most stable of all the elements.

Smaller elements will tend to move towards iron usually by quantum tunneling fusion, and larger elements will eventually decay down to iron (if the proton doesn't decay) eventually iron will through quatum tunnelling become neutrons, and/or blackholes where they evaporate with hawking radiation.

If protons do have a half life you won't have to wait as long (unless the half life is extremely longer than the current estimate of what the halflife is believed to be now).