If Trump loses, I expect the Republican base will be adrift in the wilderness, waiting for a new charismatic figure to take back the Whitehouse. I have a hard time seeing them rallying behind another career politician: Dan Crenshaw is the only one who jumps out as an obvious possibility. I wouldn't be surprised to see someone like Herman Cain emerge from the political dead to win the nomination. Or someone we haven't even considered as a potential presidential candidate.
Stop searching for an up and coming Republican politician, and start thinking of ambitious celebrities with the right profile to strike a chord with GOP voters.
You don't think Ron DeSantis could fit the profile? Young, popular governor of a huge swing state who served in Iraq and has both congressional and executive experience. What's not to like?
I think DeSantis would probably finish his second term, and he can run in 2028. They should probably go for someone with a stronger record and more experience. How about nominating a successful businessman who was also governor of a huge swing state, then beat a Democratic incumbent senator in a year that the GOP was losing badly everywhere else.