I voted for Jill Stein in 2016 because I assumed Hillary was going to win anyway, and I was in a solidly red state so fuck it, might as well vote 3rd party.
Then Trump won.
Then I learned about Stein's backwards views on nuclear energy, GMOs and vaccines.
Then she turned out to be a Russian asset.
Then she decided to run again and again, knowing that she's only acting as a spoiler for the Dems.
Boy did I make a mistake in 2016. I wish there was a perfect candidate for everyone to vote for, but unfortunately keeping Trump out of the white house is the best we can do. Harris isn't my first choice, but I voted for her on behalf of all of the people who will suffer under another Trump presidency.
Your scenario implies Trump lives to 98, and unless the preservatives in big macs are the key to longevity, I doubt he makes it that long.