Looking closer at the benchmarks, it seems that C# benchmark is not using AOT, so Go and even Java GraalVM get here an unfair advantage (when looking at the non SIMD versions). There is a non trivial startup time for JIT.
> var rounds = int.Parse(File.ReadAllText("rounds.txt"));
> var pi = 1.0D;
> var x = 1.0D;
> for (var i = 2; i < rounds + 2; i++) {
> x = -x;
> pi += x / (2 \* i - 1);
> }
> pi \*= 4;
> Console.WriteLine(pi);
On M4 Max, Go takes 0.982s to run while C# (non-SIMD) and F# are ~0.51s. Changing it to be closer to Go makes the performance worse in a similar manner.