A lot of these polls will favor the leftist until the last one before the vote.
The last one they try harder to be accurate because that’s what they are judged on for future business.
Gallup has been polling US Presidential Elections since 1936. They’re October/November polls are excellent historically and their misses don’t favor either party. Their one big miss outside the MOE? You guessed, it “Dewey beats Truman!” :-}