No. He would never win without the campaign staff and apparatus of a major political party.
Maybe that’s true as a non-incumbent. But as an incumbent president he has advantages that might more than offset losing the half-hearted support of the GOP party machinery and the tarnished GOP brand.
He’d be lucky to win a single state in that scenario. You might as well put that silly, delusional idea to rest.
Trump won’t win as in independent. It’s that simple. No one would win as an independent. All that would happen is Trump would split the vote with the Republican nominee and the Dem would win. See 1992 and 1996 for reference.