This is why I advocate for .NET in serious business contexts. You often don't have to rebuild or redeploy your software if you are using the included batteries as intended. A devops intern could handle this fix. Contrast with virtually any other ecosystem.
Instead, your software's lifecycle is entirely dependent on the OS' lifecycle. That seems worse.
And for what it's worth, it would be exactly the same with any "interpreted"/VM-based language - Java and family friends, Python, Ruby, etc. Just update the VM/interpreter and restart (the service though, not the whole server).
It's for compiled languages like Go or C/C++ or Rust that you would need to recompile. I prefer it because it ensures the lifecycle only depends on you and you aren't bound by OS versions and OS updates to be able to update/downgrade library/framework/language versions.
It's not.
.NET updates are shipped with Windows Update, but can be installed separately.
Obviously for macOS and Linux you can't get them through Windows Update anyway.