I don't think a constitutional change has to happen.
The 22nd Amendment says "No person shall be elected to the office of the President more than twice, and no person who has held the office of President, or acted as President, for more than two years of a term to which some other person was elected President shall be elected to the office of the President more than once."
So suppose Trump runs as VP on a ticket with Person X at the top of the ticket. And with a wink and a nod it's understood by all that, if they win, Person X will immediately resign the presidency. Trump becomes President again by operation of the 25th Amendment, and he wasn't elected to the office more than twice. Tell me with confidence this Supreme Court wouldn't uphold that.