I'm looking at the crosstabs, and noticing that this poll's sample deviates pretty significantly from the 2016 exit polls. Examples: In PA, 2016 exits for education level showed 22 HS diploma or less, 30 some college, 29 bachelors deg, 19 postgrad. This poll's sample shows 37-28-21-14. In MI, 2016 exits showed some college or less 58%, bachelors degree or higher 42%. This pol's sample has those numbers at 69-30. Also in MI, 2016 exits showed party ID at 40 Dem, 31 Rep, 29 Ind. This polls sample is 29-24-44. Not saying that these numbers are necessarily wrong, but it would be interesting to hear the pollster's explanation as to why they think the 2020 electorate will look so much different than in 2016.
As far as education goes the Sienna crosstabs are probably more in line with what the actual 2016 electorate looked like. The CNN Exits drastically overstated how educated the electorate was. For instance in PA, while the exit said 41% of the electorate was college-educated whites whereas the Center for American Progress' post-election analysis of the voter files pegged the number of college-educated whites in the electorate as closer to 30%.