With polling as well, discussing 2020, it's important to note that most national polling and state polling (Wisconsin being the exception) were pretty close on Biden's share of the vote.... for instance, he was generally pulling 51-52% in a lot of the national polling that year, but polls underestimated Trump's share. This is a big factor in the "miss"
Fast forward to four years, Harris has polls where she's pulling a similar share to Biden, but Trump's share is polling a lot higher in 2024 than it did four years ago. This doesn't mean that polling error isn't possible in 2024, but it does tell me that if it happens, it isn't going to happen exactly like 2020. And it's a possible data point to suggest that pollsters might be having a better time picking up Trump's support versus previous cycles.