I have drove in 49 out of 50 states (never been to Hawaii) and Illinois ranks the worst in my opinion. It’s like they ran out of asphalt and stopped doing any repairs 10 or 20 years ago.
To people not living in the U.S., feel free to complain about your country’s roads too.
Illinois was tragically underfunded due to a combination of factors, many of them stemming from previously underfunded pensions. Roads are very expensive to maintain in a climate that has wild swings between far below freezing, and extremely hot and sun baked. 2021 (the year that your link was posted) was around the time that the funding crisis was being addressed.
https://idot.illinois.gov/transportation-system/rebuild-illinois.html
Illinois more recently has new actual adults running the state and is working to repair the underfunded problems of the past.
That being said - Most places that have better maintained roads have significantly lower temperature swings, and very stable land.