I've been looking at some polls and things look much better for dems in the mid-terms. On the Biden approval rating, I don't think it will ever get very good and believe a major reason for that is his disapproval within the democratic party and especially among young voters. Basically I believe the major factor in his disapproval is his age; plain and simple. That's not to say there aren't other, legitimate reasons, but I think that's the biggie.
It's also the reason that his low approval ratings aren't adversely affecting the down ballot candidates to the extent you would expect (although his ratings have gone up substantially over the last month or so). There is, I believe, overall pretty high approval for the policies of the dems and disapproval for the policies of the repubs.
When I look at Biden's overall record, I'd probably give him maybe a "B". What I wish people would realize more broadly is that IF the dems can somehow hang on to the House (unlikely at this point) and win a few key races in the senate, we are going to get a LOT more infrastructure bills, corporate tax revenue, climate change funding, research, etc. signed into law. I also wish they would realize that the problems have generally been Manchin and Sinema and not Biden.