I listened to a professional pollster on the radio the other day. He said that a lot of polls are wrong when it comes to gauging republican or conservative voters.
With the attacks on social media, doxxing, arrests and so forth; a lot of republicans and conservatives are reluctant to answer any telephone or online polls.
They are afraid that if someone finds out, regardless of the promise of confidentiality, that they or family members will be attacked.
Just look at the surprise on the Trump victory in 2016. Remember that Hellonearth Clinton was supposed to win according to the polls.
IMHO, a lot of polls are wrong about the conservative undercurrent in US politics. The only way the democrats can win in the midterms is by cheating.
If it worked for the big one in 2020, they will use it for the little elections elsewhere.