This is a tough one. I think Bernie could have beaten Trump 4 years ago, they were both outsiders with the same message: bring back manufacturing, change the US's trade deals, drain the Washington swamp. But Bernie was a much more credible candidate.
Now with Trump actually in the White House and 'delivering' on his promises to shake things up, I think it's a stretch to think Bernie could beat him.
I also think Biden will get beaten soundly, so basically 4 more years either way. So depressing.