> Reading your article again, I wonder whether your compiler is just not doing the right things to take advantage of the performance boosts available via CoreCLR?

> E.x. can you do things like stackalloc temp buffers to avoid allocation, and does the stdlib do those things where it is advantageous?

The C# standard lib (often called the base class library or BCL) has seen a ton of Span<T>/Memory<T>/stackalloc internal usage adoption in .NET 6+, with each release adding more of them. Things like File IO and serialization/deserialization particularly see a lot of notable performance improvements just from upgrading each .NET version. .NET10 is faster than .NET9 with a lot of the same code, and so forth.

Mono still benefits from some of these BCL improvements (as more of the BCL is shared than not these days, and Blazor WASM for the moment is still more Mono than CoreCLR so some investment has continued), but not all of them and not always in the same ways.