Nah. Shy Trumpers is a well known theory, not a fact. Really, the numbers from 2016 didn't really show that so much. (Trump was generally overestimated i blue states and underestimated in red)
It was about late deciders. Trump won those by a landslide 4 years ago. But it doesn't look like they are as many this year. Polling generally has less undecided/3rd party voters (4-5% nationally compared to 12,5 % on election day 2016).
Let us afterall look at the polling averages from 2016. They were generalle pretty correct when it came to Clinton. They underestimated Trump but didn't overestimate her (in fact she ended up higher in several states). Now Biden is generally higher in polling than Clinton, even being above 50 % in Michigan and Wisconsin.
Unless people are suddenly saying that they will vote for Biden just to end up voting for Trump, there aren't much "shy Trumpers" to change the direction of the election.
We have seen a few bigger misses in polling than what would be needed for Trump this year, but it would be pretty damn big.
I'm not calling anything, but I'm having a hard time believing that you'll be right.