I've been thinking since the summer that Romney would run for President again. He'd be 77 in 2024, but he probably thinks if Biden can do it then he can too with the platform of restoring the Republican party. After seeing how many votes Trump got this election, it shows Trumpism is alive and well and Trump would beat any 2024 primary challenger as long as he doesn't get indicted. Or some wannabe Trump may have a shot since the part moved to the extreme right.
Doubt Romney runs. To be honest I could see him retiring after the end of this term.
Like you said, he'd be 77 by then and would lose to Trump or whoever the most MAGA candidate is.