Both candidates have admitted their internal numbers look closer than the public polls. That's because they use different measures, small groups of "likely voters" is not really representative.
The Biden campaign made a tremendous mistake calling a lid every day and staying in the basement for the last 2 months. They were thinking the media was going to cover for them and they did. But now the Hunter Biden story, Trump exposing the deep corruption within the Biden family on public television, the first time ANY major network covered these facts, the failed censorship and exposing deep corruption ties with social media (both Twitter and Facebook spokespersons on the issue were proven to be Biden plants) and failing to stack the debates in their favor put them into a frenzy and now Biden is hurriedly tracking all over the country.
They've been going so fast, even Kamala Harris doesn't know where she is at any moment, asking on a hot mike the other day whether she was in Cleveland (https://www.youtube.com/watch?v=cFe5pqJ_MtA).