Trump's badness is not transient at all, if anything his unpopularity is the most stable in the history of polling. Seriously not only is what you're saying wrong, it's the polar opposite of reality.
Anyways, I certainly couldn't guarantee that Biden will win, unlike how you're guaranteeing he will lose. I find it foolish to put such certainty on something when if anything, the data indicates he will more likely than not win.
If you really are this certain though then you stand to make a handsome profit in the betting markets. I hope you're taking advantage of the opportunity.