Every poll is going to have its flaws. I'd say the best thing is to look at what they said about the 2016 race at the same time and see how that translated to the result. Around this time in 2016 most polls had Clinton 2-3 points ahead nationally, which is how it finished up - but state polling was more off last time. Whether that has been corrected this time...?
On the small margins, they're not actually that small in real terms.
(The 538 poll aggregate, tipping point is where the 270th electoral college vote comes from).
So as things stand Biden has four or five states of leeway.
Florida has got a lot worse for Biden, but Ohio, Georgia and Iowa have got worse for Trump. Trump's lead in Texas is shakier than Biden's lead in Arizona which Trump won last time. And in the next month he needs to turn some of that blue into red. In the last six weeks it's not moved much at all.