I've used VM's for years to run Windows on top of macOS or Linux on top of Windows or macOS on top of macOS when I need an isolated testing environment. I also know that Java works via the "Javascript Virtual Machine" which I've always thought of as "Java code actually runs in its own lightweight operating system on top of the host OS, which makes it OS-agnostic". The JVM can't run on bare metal because it doesn't have hardware drivers, but presumably it could if you wrote those drivers.
But presumably the VM being discussed in TFA isn't that kind of VM, right? Bytedance didn't write an operating system in Javascript?
I've been seeing "VM" used in lots of contexts like this recently and it makes me think I must be missing something, but it's the sort of question I don't know how to Google. AIs have not been helpful either, plus I don't trust them.