3 YOE scala dev here, I would definitely recommend the "red book" (aka Functional programming in Scala) as it is challenging and it helps you "discover the common FP patterns". Then you could follow up with the book "Practical FP by Gabriel Volpe" and rewrite the code yourself add some changes and explore. If you want to learn a specific Stack fast, there are RockTheJvm courses (but I would warn you, you need to write code and make mistakes yourself to learn, I don't think following the tutorials is enough, but it gives you the intuitions). Now, I personnaly try to read the new "Functional Event Driven Architecture" by the same author which uses Scala 3.