For context, when I first became aware of the Mark Seemann, he was very deep into the object-oriented way of doing things. I discovered him because he was the author of (the excellent) Dependency Injection in .NET. A while after writing that book, he started getting into F#, and eventually Haskell, and blogged about it all the while. The upshot being, his blog archive now tells a fascinating story of the evolution of one person from being a an extremely accomplished object-oriented programmer toward being a serious functional programming advocate.
He's also done a very good job of explaining what FP has to offer to an object-oriented programmer, or at least one who likes a certain style of OOP. For example, see https://blog.ploeh.dk/2017/01/27/from-dependency-injection-t...