(Disclosure: I get paid to work on .NET)

The good thing is that the older techniques to minimize allocations still work, and tools like refs and ref structs make it easier to write zero-allocation code than it used to be.

But it's definitely harder to reason about whether optimizations will 'light up' for code that uses heap-allocated classes, closures, etc. than it was in the past, even if it's harder for a nice reason.

BenchmarkDotNet is a fantastic piece of tech at least, I have found it easier to benchmark in C# than in most other ecosystems I work with.