Yank in the UK here.
I predicted a Trump win last time around and was told I was crazy, even paranoid. "Stop being so paranoid" I was told, "She'll win Florida and it'll be over." Nope. I 'knew' for sure about 8 pm UK time when we were watching BBC coverage in the US, which was very subdued. It felt like they were onto something. The US news channels were not picking it up at all, still quite bullish on Hillary. I'm not saying it wasn't horrendous to take in but I was not surprised overall.
I am not sure what will happen this time yet, because of Corona virus, but Biden could definitely win. It is not a done deal for Trump by any means. He knows this, too.
What could happen is that Biden wins an even larger portion of the popular vote - in states that are already 'blue' though, so loses the Electoral College again. Basically a doubling down of what happened to Hillary.
But I don't think so. I think he will win states that Hillary lost marginally last time - she some on very few votes indeed and the African American vote is much more solidly behind Biden. Hillary went into the election with a divided Democratic party, let alone nation. Biden has won the nomination convincingly. I think more Sanders supporters will back him.
Hillary was very unpopular with more people than her supporters care to admit. I have many friends who are Ride or Die Hillary and I do keep this to myself. One thing that has occurred to me about her is that she never really convinced as an Obama supporter either - it did feel like she was just waiting her turn, even then. My instinct is that this amplified Sanders' ability to play on a sense of Clinton bias in the party. I do think there is misogyny in the US too which means people won't vote for a woman President for some time yet. A conservative one - maybe.
Of course Hillary was the more qualified candidate and would have conducted herself with all the dignity Trump clearly lacks. But voting is often not rational, just instinctive.