I don't think there's any evidence that the Ukranian prosecutor at the time was even considering re-opening the investigation. If anything, by getting that prosecutor fired Biden made it more likely that the Burisma investigation would be re-opened. If you have any evidence to the contrary I'm all ears.
Your concept of burden of proof is so twisted I am not sure what the point is. Your standard is what you think some guy you don't know was thinking at the time, and since I don't have any evidence he wasn't thinking about re-opening it, then we must assume he wasn't. This is a seriously weak form of debate. For the love of God please just take some basic logic courses. Maybe learn about scientific method, empirical data, and burden of proof while you are at it.
Yeah. I think it's reasonable to assume that a prosecutor is not going to re-open a case that was closed years ago unless there's some reason to think otherwise. Especially when there are allegations that the prosecutor was bribed to close it in the first place.
To assume that Biden "bribed the Ukrainian President with $1 billion dollars to fire lead prosecutor investigating his corrupt son in 2018" while there was no investigation seems pretty illogical to me. It just doesn't make sense.