I don't know why Biden would cause so much inflation in Canada, England, France, Germany, and just about every other country on earth, but he did. What a dick.
Obama is also at least 10% to blame. Vote Trump 2024 to teach the Dems a lesson.
We'd need to know the exact change being referenced. There are lots of couldas. Don't get me wrong, I agree that it's possible, but there's not much to discuss without more info.
Unilaterally? No, nothing Trump couldn't have changed with the stroke of a pen. Could Congress have? Sure. Did they in this case? Who knows. Is Obama specifically to blame? Very unlikely.
Unilaterally? No nothings like that, but thats how laws work. And another things laws tend to do is give a window of correction to abide by such laws. And you seem to discount that.