you don't necessarily need to buy a new PC, you can spin up a VM

Yes - that is probably a good way forward.

I was thinking that having a Linux box as a separate machine, I might use it as a desktop for some productivity tasks and learn more about Linux in the process. But that would dilute it from being much of a replica of the webserver so perhaps better as a VM. Learning more about Linux is one of those things I have thought I ought to do for the last 20 years or so. But I would find it difficult to articulate why I should...