I think people are underrating the possibility of a 'shy' COVID backlash vote. There is a difference between people's stated preferred COVID policy and their actual behavior, and perhaps in a ballot booth they just decide " It" and choose Trump instead of Biden if it means less COVID lockdowns. Not that this is likely, but I think a COVID lockdown backlash is more likely than a backlash against the BLM protests.
Either way, I think the media will just blame it on the polls. Although maybe this time they'll actually listen to the polls if they indicate tightening instead of pretending it was mid-October still.
I remember hearing how lockdowns are somewhat popular back in the Spring (not now) and I think Biden saying he wants a mask mandate is a lot more tamer than a lockdown. So I do not think you'l see that.
I think a lot of people will look to Trump's improvements among Black and Hispanic voters than anything else.