Assuming Trump wins, his VP would have the inside track to being the early frontrunner. That's maybe Elise Stefanik, Tim Scott or Joni Ernst.
If Trump wins:
Whoever he picks as VP is likely gonna be his handpicked successor, unless said VP crosses him, in which case he'd just crown another MAGA goon to take the nomination. Hell there's a good chance his VP will be the incumbent President and end up running unopposed for the nomination.
It looks like Trump is not selecting a VP to be the heir in 2028 and there’s a strong possibility they end up not running.