I work in the maritime domain for the Norwegian gov., where we've had a couple of demos. AFAIK, there's only one agency here that uses Palantir software - the customs service - and that's not any secret info.
But we frequently work with people from adjacent fields (military, law enforcement, aviation, other maritime, etc.), basically the usual suspects as far as Palantir clients go.
My observation has been that there's no strong push or even desire to become a customer. The people I've talked with have either been outright unimpressed, or have already similar systems they've rolled out themselves.
From the demos we've had, it seemed to me that Palantir can do well in countries where all the potential clients are isolated from each others (disorganized even), and do not have and good means of sharing data / communicating with each others.
There's a lot of hype, myth even, around what their tools do - and I can understand why many are just saying "no thanks" when they come knocking. It is sort of underwhelming.
Don't worry, they'll buy your boss's boss nice dinners and box seats at sports games until they see the light.
Organizations that are already running well with solid operational processes and data governance won't gain a huge benefit from Palantir. They can only add a lot of value in organizations full of lazy, incompetent people. This describes many government agencies. But not all.