I seriously doubt that a 3 point national victory would give Biden all of the key swing states except Georgia. The way things are looking now a 3 point national win seems unlikely to actually be enough to get to 270.
If the margin narrows in NY and FL becomes safe R, it's possible. Trump's EC advantage seems to have faded a bit and Biden could win with a 3 pt. margin. Of courde would better for him to win by 4-5 pts.
Theoretically, yes, but I want to see some good swing state polling for Biden before I believe it. They have been atrocious so far.
