I can see how SOLID and OOP seem to be related, but the principals of SOLID can (and IMO should) be applied to FP as well. In fact one of the clarifications in Uncle Bob’s letter hints at this, by expressing that substitution is about subtypes, not inheritance.

This is of course common in statically typed FP languages like Haskell (or FP approaches in statically types imperative languages like TypeScript, Swift, so on). But even in dynamic languages like Clojure, substitution of subtypes of a given interface is pervasive; I would even say it’s foundational to the language’s core concepts.

I’d even go further to say that FP languages and approaches are much more likely to guide developers toward SOLID naturally than imperative languages and approaches.