These articles exhorting the benefit of using FP in the small are great, but I'd been lost forever making the leap from small (<10 line) examples vs typical apps with their CRUD behavior and in general state everywhere like a db or file system or network requests and so on. I've found this talk(https://www.destroyallsoftware.com/talks/boundaries) by Gary Bernhardt way more useful in terms of how to apply FP principles in the real world.

The other grouse I have with posts like these are they try to over-simplify FP - "using lambdas is FP" or something like that. I think this leads to folks thinking 'hmm - I know how lambdas work... so if I use lambdas, then it's good' which is missing the point completely.

I think one does need to 'grok' FP concepts completely - composition, higher order functions, tail recursion, immutabililty etc and gain an appreciation of FP vs procedural the hard way before they can hope to utilize it effectively.. I think those things help you think 'functionally' which is much more valuable in the long run rather than 'how do I bolt on FP on OOP'