.NET 8 is like 1000x faster that GDScript & Python in some benchmarks. Even older Mono runtimes are like 10x faster than UE4.14 BluePrint runtimes. IL2CPP is about 3x faster than Mono and .NET 8 runtime is about 2x faster than IL2CPP making it only about 10% slower than VC++ if I remember correctly. Depends on CPUs of course but you can write low level game-engines in C# that would perform almost as well as C++ ones, maybe even better in some cases. You also have the advantage of Roslyn with code-generators, custom syntax compiler errors via Analyzers which can be used to create lang subsets to compile C# into GLSL, HLSL etc allowing the lang to be used in far more areas in very solid ways other lang compiler tools just don't allow for. UE4/5 tries to mimic some of the metadata features C# has in C++ as it ends up with a nightmare of code that literally can take the entire day to compile vs C# that would compile the same code in like 60 sec.