@SW-User Lichtman uses fundamentals that have nothing to do with polling. He was wrong in 2016 only because we're stuck with the Electoral College. The same thing could happen this year. Silver uses aggregates of polls and some fundamentals to come up with what basically amounts to a weather report.
Electoral-vote.com only uses state-level polls, averaging the ones for the past week. They consider any difference of 4% or less to be within the margin of error. As of today, they have Harris at 257, Trump at 230, with 51 tied. They've been fairly accurate. Their thinking is that errors in any one poll will cancel out if several are used. Generally, swing states are polled often, especially as the election approaches, so they have a lot to work with. They do have wonky results sometimes, like right now they have Indiana as "barely Republican" based on a poll in April that had Trump only 4 points ahead of Biden. If anyone bothers to poll Indiana again, presumably Trump and Harris will be further apart and the state will show as the solid Republican one it should be.