Kotlin strikes a good middle ground on the fast compilation <-> inference continuum IMO. within function bodies you rarely need to think about the typing system. Function return types can be inferred for expression bodies and star projections can make some of the more tricky parts of generics more tractable.

Inference is a big part of what increases Kotlin ergo over Java and while it does compile slower you are going from a very fast base so it doesn't feel slow relative to other options.