Everything I have seen about "pure functional" programming has cared more about ideology than practicality.

I had the opportunity to meet John Backus, the inventor of functional programming, when I worked at IBM. I definitely didn't "get it" the first time. Indeed, not until many years later.

I wrote this article, Functional Programming in TS[0] which has a lot of good background info and explanations. At least I think so, lol! And it's been pretty popular. See what you think:

[0] https://medium.com/gitconnected/functional-programming-in-ty...

Every concept is good when applied in the right place for the right cause. But programmers often tend to idolize particular tech to the degree that anything else is anathema.

Indeed. If the goals of functional programming help out in a particular instance and that style works for you, then use it.