This pollster has a long history of overestimating Democrats
But even without that, if her approval is really -7ish and she's getting the same percentage as that in a matchup, with Republicans way below her disapproval, it matches the same phenomenon we're seeing in national generic ballot polls of Biden's approval being low 40's and Democrats basically getting that but Republicans way below his disapproval. This certainly didn't happen with Republicans in 2018, who were down in the dumps right away, and it didn't happen with Trump in 2020, who consistently polled below his approval rating. I don't know exactly what's causing this besides shy R-leaning independents, but if it doesn't change you can expect polling to continue to overestimate Democrats. Needless to say, pushing the undecideds should garner a more Republican result. The idea that today Whitmer would win by a larger margin than Biden did in 2020 is pretty crazy and well outside what fundamental indicators would tell us.
But I honestly expected this after 2020. I don't think R's are going to lead in many states they will end up winning. I'm only waiting for the point where the polls make people's predictions more Dem-friendly than they started out as based on fundamentals, as they did starting in the spring of 2020, and then we'll see if history repeats itself.
Most Pollsters still haven't learned their lessons even after 2016 and 2020. Can't wait what garbarge CNN/SSrS is going to show! NBC/Marist State Polls were a complete crap in 2016, 2018 and 2020.