Yes, it pretty much depends on what and how you're trying to compile. Incremental complication helps a lot, as does keeping sbt shell open and not restarting sbt each time.

In other news: now, there's scala-cli for smaller projects — https://scala-cli.virtuslab.org/docs/guides/scala-js

this is true. ReScript/OCaml compiler is super speedy. Scala/sbt builds can usually be optimised quite a bit few people know how or bother to