I cannot help but read this whole experience as: “We forced an engineer to take sales calls and we found out that the issue was that our PMs are doing a terrible job communicating between customer and engineering, and our DevOps engineer is more capable/actionable at turning customer needs into working solutions.”
I find if you sit engineers down with whoever is doing the operational work, you very frequently find you don't need PMs and everyone is much happier.
PMs can be incredible, but my experience is that they tend to be both very territorial and know surprisingly little about either the engineering or the customer side of things.
When I design a UI, it's clearly a programmer's UI. But I try very hard to make things as clear as possible and I'm usually wrong. When I see people struggling to use a tool I made, it means I have failed at design and need to fix it.
It's my belief that if you grab a random person off the street and they can't figure out what your product is or how to do even the basics, you have failed to design your product. In 100% of cases, a user should be able to walk up and figure out the basics after a few minutes of poking.
If a user needs to check documentation before they can accomplish any task, your design is bad and you should feel bad. If a user needs to inspect every tooltip every time, ten million years dungeon.