Problem with polls is same as in 2016 and 2020. With how demonized Trump is, people just too scare to say they would vote for Trump.
That's absolute confirmation bias. With the exception of the most populated places in the country, there are very few people emboldened to wear or show off
anything proclaiming Democratic values at their homes, clothing, or vehicles. Conversely, you don't have to ask if someone's MAGA, they'll tell you...
In real life within America, many people will not discuss politics in polite company, so there is generally no way of knowing. It depends on context; in a crowded place or amongst strangers, it is generally (somewhat) taboo to discuss such things in a public setting. It's considered divisive around strangers, because one generally seeks generally a calmer and easier path to acceptance, rather than immediate difficulties. At home, amongst your peers, like-minded individuals, and The Internet; it is totally different; you can be as brash as you want and get away with it*.
Source: I have personally been to 48 states since the dawn of 2015; accounting for travels in roughly 25-33% of the counties/parishes in America (there are 3143 of these units** within all of the states).
* House rules may apply. See terms and conditions for details. Closed-minded driver on an open course. Wear your seatbelt.
** Yes, I count them.
I reckon there's definitely an embarrassment (even shame) factor about voting for Trump - and that this likely does affect polling.
With a bit of luck, however, people who are too embarrassed to admit they intend to vote for Trump might actually stop to think why they are going to vote for Trump before actually doing it. It says alot about the GOP that Trump is still their candidate, in spite of being so unbelievably horrendous a person - and I would imagine that there is a large swathe of GOP voters who would much rather be voting for someone else as their President. I reckon the same cannot be said for the Democrats, so there is likely some bias in the polls because, simply put, admitting you're a Trump voter is (and damn well should be) a real embarrassment.
The phrase "lesser of two evils" has been a part of democratic politics for decades, or probably at least well over a century, I'd guess. So there's always going to be those that hold their nose and vote, and probably have nothing much to say on the morning after Election Day and move on their their lives. There's always percentages that don't show up to vote or don't care one way or another, traditionally among younger demographics.
"Shame" definitely depends on the environment. In my city of 250,000 there's likely a little more shame in wearing a red hat in public, especially in a large public gathering. Step outside those confines of the city or the large group, and he's the golden calf with a tinfoil hat in a lot of places. Just the same, there are seriously racist and sexist card-carrying Democrats out there who will probably not vote and will be even more silent.