That being said, I'd much prefer to deploy a C# application over Node or Java, no argument there. But saying "I wish more startups were using C#" makes me wince. C# seems well-suited for the monolith-architected VM-image-deployed strategy of the early 2000s, but it's pretty close to being the exact opposite of modern best practices. And unfortunately it's kinda unfixable in a language that depends on a VM execution environment.
I'm sure all this is short-lived however -- I'm relatively confident we'll see deployment best practices converge down to "use whatever language you want but you must compile to WASM" in the next decade, so the warts of devs' chosen language aren't an ops problem anymore.