To me a claim "how many things the Java ecosystem gets right that .NET gets wrong" borders on insanity if we consider having to interact with Maven or even Gradle on a daily basis after .NET's CLI and NuGet, or having to deal with type erasure in generics, or weird stream API shape, or not having common slice and sequence types that everything nicely unifies under because primitives cannot be generalized, or not being able to author properties and extension methods, creating dozens upon dozens of type copies or just boilerplate accessors, or having to tolerate Hibernate after EF Core, and so on and so forth.

As for async and tasks - have you ever considered just not writing the code that is so bad it managed to bypass cooperative blocking detection and starvation mitigations? It's certainly an impressive achievement if you managed to pull this off while starting with .NET 6.

Edit: I agree with the subsequent reply and you are right. Concurrency primitives are always a contentious topic.