Just two weeks ago, Australian World Tour pro rider, Tiffany Cromwell, raced Paris-Roubaix and finished 16th. The Olympian and winnaar of 2021 BWR Kansas had an interesting answer when asked which was harder, BWR CA or Paris-Roubaix?
The third place finisher said, "BWR was harder than I expected... it's harder than Paris-Roubaix."
We can attest. This was the hardest BWR course to date. It wasn't the longest nor most elevation gain. That goes to the 146-mile / 12,000 feet of climbing 2016 version. But this course, with the extra and very challenging unroad sectors, was the hardest.
There is a cool look at the BWR courses over the years here: https://www.gravelstoke.