Optimizing for people that are new to a codebase seems like a mistake to me: onboarding costs are relatively minimal and finite (per developer) whereas maintenance costs have no fixed bound: if generics let you exclude invalid states by design (and they do: this is one of the biggest advantages of parametric polymorphism vs. interfaces), they will be useful for keeping maintenance costs under control.
You definitely want to optimize for people who are new to a codebase. Over enough time, the codebase grows to a point where essentially _everyone_ is new to each area of the code, because nobody has touched that code in 2-3 years and the person who wrote it may not even be with the project anymore.
Even for your own single-person projects - if you get fancy with the code, 6 months later you find it's a lot harder to get back into and mess around with than if you had written the code as though you were presenting it to a beginner.
Management is responsible for making sure that doesn’t happen, by retaining experts and demanding documentation and investing in ramping up new experts. Making the code bigger because each line does less is not going to save us from nobody understanding prod, and a short learning curve puts a low limit on the value of our staff (who quickly run out of tools and stop improving in clarity and productivity).
You want patterns that are well-known to the maintainers, but this is different from “optimizing for the new”: consistent idiomatic use of a library like XState or Ramda in a JavaScript project can cause a high onboarding cost (because the new developers don’t know the library well) without any corresponding ongoing cost.
I’m guessing you like Haskell and similar languages, because that’s the natural conclusion to your line of reasoning.
I don’t agree with you, but I could be wrong. There are plenty of languages that are aligned with your point of view. I like go because it was going a different direction, and I hope that doesn’t change. You can use Haskell, scala, typescript, etc to get what you are looking for.