This is nuts. More than a decade ago Microsoft made a big deal of startup optimisations they had made in the .Net framework.
I had some Windows command-line apps written in C# that always took at least 0.5s to run. It was an annoying distraction. After Microsoft's improvements the same code was running in 0.2s. Still perceptible, but a great improvement. This was on a cheap laptop bought in 2009.
I'm aware that .Net is using a different runtime now, but I'm amazed that it so slow on a high-end modern laptop.
To be fair, this is timing early bits of a preview feature. Compiled .NET apps have much better startup perf.
This is also a preview feature at the moment. They mention in the embedded video that it is not optimized or ready for production scenarios. They release these features very early in preview to start getting some feedback as they prepare for final release in November.
They are not on Windows. As someone else pointed out, there are very likely Apple-specific shenanigans going on.