Yes, I'm with you on all of that, I just want to point out the last part - the "makes it even worse" part - needs to be zoomed in on in full detail here to make sure the proper amount of blame (a fuckload) gets spread among the proper targets (several). AW has his hands in running not only the insurance and managed care side of things, which he and BT probably very well did collaborate like you described, but he also had his hands in running Optum, which according to the UHG wiki was involved these things:

It is organized into three businesses:

• OptumHealth – provides primary and secondary care.[74][75]
• OptumInsight – provides data analytics, technology, and operations services.[74]
• OptumRX – provides pharmacy services.[74] https://en.wikipedia.org/wiki/UnitedHealth_Group#Organizational_structure

So I really feel like highlighting this Andrew Witty guy as being extra-Brian Thompson is something that should be highlighted. AW was playing all sides of the healthcare system to maximize profits. Insurance, sure, but also they were working it from the angles of also owning the doctors in primary and secondary care, plus pharmacy services, plus an entire data farm operation that was most definitely not meant to make sure customers get maximum access to healthcare. He's just an extra-super-mega fuckstick, beyond what I feel like I can put into words, you know?

edit: also, there are CEOs for all the other subsidiaries, naturally, but the point really is that the folks at the various Optum businesses and the folks at the various UHC businesses all had different focuses in how they fucked people, whereas Andrew Witty was the head of the company that had the unified vision on how to utilize both divisions to murder more people that either could have done independently