From the leaked intelligence documents (see https://lemmygrad.ml/post/594109 ), even the military is working off of Oryx and whatever the Ukrainians tell them. In other words, the capability to properly assess their foe is already compromised by deliberate propagandizing before the usual friction that makes assessment difficult.
For the regular congress people who are supposed to hold a leash on the military, their information is most certainly from regular newspapers and think tanks who are on the slava train. It was only it became impossible to lie and obfuscate success that the newspapers and think tanks walked away from unconditional slavaing.
I don’t know if this could be considered “good news” or terrifying news. If the US has such a lack of understanding of their own capabilities, they’re likely to push much more aggressively, thinking they would automatically win. On the other hand, their lack of understanding means they would fall short in an actual war with a comparable military to their own.
