In order to prove Biden committed treason you would need direct proof that he was involved in a conspiracy to commit fraud to steal the presidency. That would be very unlikely.

If AZ decertifies the election either through the Legislature (unlikely because of the razor thin majority) or more likely through the courts (still highly unlikely). This would create a Constitutional crisis with a ripple effect to trigger more states to investigate and or audit. It could come down to a special election or Congress voting for President with one vote per state.