If you have a recent enough and powerful enough Chromebook, then you should consider Crostini, which can give you a Linux container running in a lean virtual machine in your Chromebook.
If you have an older Chromebook, you can consider Crouton, which can give you a chroot with a Linux distribution into your Chromebook.
Both approaches will allow you to install a Linux distribution such as Debian or Ubuntu into your Chromebook, which will allow you to have a native Vim package which is able to spawn a shell and run all the standard Linux utilities.
The advantage of the former approach, Crostini, is that you're running on a lean virtual machine that allows you to keep all your Chromebook security features enabled, so you should prefer that approach if it's available for your Chromebook.
The latter, Crouton, requires that you switch your Chromebook to developer mode. There are security implications to switching to developer mode, so make sure you understand them well. The Crouton page and wiki include pointers to information about that, so I'd recommend you start with those.