-No; Bernie and Joe Biden would both have won. Trump was an exceptionally good candidate for some sections of the country (e.g., Eastern Ohio), but he was hardly unbeatable, and was an exceptionally bad candidate for the elite areas. With a more credible Democratic opponent, he could have been beaten.
You saw where I said that arguments exist that other democrats would have won? That I could come up with some myself? So you provided one. But you saying it doesn't make it true. The point is we won't know and can never know if it would have played out that way. It's just not as cut and dry as you're making it sound. And you stating matter-of-factly that Sanders and Biden would have won, doesn't make it true.