To the extent that I understand your complaint, there is a functional architecture that alleviates this concern: arrowized functional reactive programming. https://blog.jle.im/entry/intro-to-machines-arrows-part-1-st... talks about it.
The problem (truly the problem) is about _where_ one defines behavior. It's the expression problem (EP) at its core. A FP approach separates data and behavior in a way that makes adding new behaviors to the same data types easy and OOP combines them in a way to make adding new data types to the same behaviors easy. It's literally the difference between:
let model' = update model msg
let model' = model.update msg