A few things:
1.) Pollsters obviously aren't broadcasting means and methods because they are trade secrets, but it has been reported many have adjusted from 2020 to try to capture any weaknesses missed. (As your post suggests)
2.) In 2020, we were in the midst of a once-in-a-lifetime pandemic that had real world impacts in many ways, including in sampling as well as how each party undertook campaigning (ie. Dems were not canvassing in person) and what method people used to vote. Obviously could have impacted polls as these real world impacts are hard to model.
3.) Going off recollection here, but IIRC, Biden's margins were strong, but he was often polling at or around 50% in a lot of these states. IOW, polls were decent in finding Dem share, but had trouble finding Trump's share. Using the 49-46 result in the Suffolk PA poll as an example, there are far less "undecideds" and likely is closer to what a final outcome would be like than a lot of the polling 4 years ago would have shown