As someone who lives in the US I'd kind of prefer if people didn't flippantly mislead my countrymen to claim that assassinations are beneficial. I found zero sources on Wikipedia for what you claimed. Seriously, if you are too "bothered" to look up any source for an empirical claim, perhaps you should reconsider posting the claim in the first place.
Here are several articles about denial increases in the time immediately following Thompson's death:
So the "factual answer" actually is false, and you can't be bothered to even do a google search, you're just spreading misinformation for fun and spite.
The claim was not "UHC made prior authorization easier for many procedures," the claim was "rejection rates by health insurance companies plummeted." I found several sources claiming that denial rates increased following the assassination:
But Wikipedia has a comprehensive list of reactions with citations: https://en.wikipedia.org/wiki/Killing_of_Brian_Thompson