TinyEMU is a system emulator for the RISC-V and x86 architectures. Its purpose is to be small and simple while being complete.
It has a javascript version, JSLinux, that's embedded in the pdf. You can run other OS-es in the browser with that, see link. It has X window support, so it should be possible to run a full GUI operating system in a pdf.
If your not running Linux inside a PDF, inside a browser, inside WSL, inside Windows, inside the Linux version of virtualbox, inside FreeBSD jails, on a Arm System inside a x86 emulator than what are you even doing