As one data point, "slow Scala compiles" was the #1 biggest developer complaint at my company when I joined in 2017, and nowadays that complaint doesn't even break the top 10. Scala compiles are not great, but not terrible.
A lot about Scala sucked in 2015, and I wouldn't recommend 2015 Scala to anyone, but it's not 2015 any more. 2021 Scala is what I'm talking about