Trump will be 78 in four years. I don’t think he’ll try again if the presidency is stolen from him this year. I’m not at all confident that there will be any meaningful election at all in 2024, but I’m reasonably sure that Trump will not be a viable candidate.
Trump would be the only viable candidate. Only Romney and Christie will be dumb enough to run against him, and Trump’s plan is obviously to continually campaign over the next 4 years.
He is the leader of the Republican party.