I don't know why the snark to the first point. It is just one poll and one poll that has really funky cross-tabs and results. I'm a huge fan of polling, but that's how it works- you should look at polls holistically. There's no indication that say Biden is going to lose Nevada by 11 points. And it is one poll a year before the election. General election polling this far out is not predictive.
Also re: presidential approval, in recent years it is completely partisan. Trump had one of the most stable approval ratings historically, mainly because the people that hated him hated him and the people that loved him loved him. It has become a much less valuable indicator than it used to be as we are so polarized.