Every scala code base I have worked on, that wasnt written by small team of experts, turned into a huge pile of crap. A small squad of people that treat the language like a religion create an impenetrable masterpiece
And with the arrival of virtual threads in the JVM there are new concurrency libraries e.g. Ox [1] and Gears [2] which remove the need to use FP concepts like monads. Which have been the major source of much of the complexity.
For all its problems it is a seriously under-rated platform especially Scala.js which IMHO is far better and simpler than Typescript.
You can optimize your codebase to be modified by an ever rotating group of people who don't fully understand it, or by a smaller group of people who do. Both are legitimate choices in specific contexts. But if you take a codebase written one way and try to maintain it the other way, your productivity will tank.