Scala is a great language. It's a little bit disappointing that Kotlin is the JVM language that's gained so much traction instead.
I've used both fairly extensively. Scala is just "too much". Kotlin is perhaps not enough, but that's better than too much.
They really obliterated their momentum with how they went about Scala 3, unfortunately.
Except when you chain many collection operations... then it breaks horribly.
I was first a big fan of Scala, and while I still like it, I am now really into Kotlin.
I don't find it disappointing: I tend to consider that Scala was an inspiration for Kotlin. Maybe Kotlin won by being simpler, and definitely because of the tooling and community: being backed by JetBrains and Google helps.
For a long time, the tooling was very limited with Scala, which must have slowed its adoption, right?