And the amendment itself exempted incumbent Harry Truman, who had served by succession almost all of FDR’s 4th term and been elected to his own term between it being passed in Congress and ratified by the States.
Even if the answer is no, everyone eligible to be president can be elected at least once under the 22nd Amendment (nobody is barred from ever being elected based on time served), so your career VP could still rack up however many years and then be elected once in their own right no matter how you interpret “more than two years of a term.”
Gerald Ford, as it happened, was invited to become vice president again, by a man who was elected president and then came pretty close to dying just two months after his inauguration. So Ford could have served a little more than six years as president and then been elected once in 1984, for a total of more than ten years.
I recall a discussion earlier that mentioned if the house speaker were ineligible to become president, i.e. foreign born etc. - but the job fell to them - they’d be passed over for next in line.
Good point. That’s exactly what I was trying to sort out.
So no max years anyone can be President, but to get past 10 years it would take events extremely unlikely to occur.