[qubes-users] Configuration Files, Nested Virtualization

So I have been trying to enable nested virtualization so that I can run Virtualbox in a Windows HVM, but I am running into issues. I was trying to follow the instructions from the Xen wiki, as well as this https://groups.google.com/g/qubes-devel/c/UzO0BsIfIow/m/C7us11XHAwAJ post, but I am new to Qubes so I didn’t realize that it no longer uses individual config files for AppVMs. I found this https://groups.google.com/g/qubes-users/c/K8lfxC8xdp4/m/jGwC-gxnBAAJ thread, and am now trying to create a custom config file in /etc/qubes/templates/libvirt/xen/by-name based off of the default xen.xml file, but I am not sure how to edit the file in a way that would allow nested virtualization in my windows vm.

my kay:

So I have been trying to enable nested virtualization so that I can run
Virtualbox in a Windows HVM, but I am running into issues. I was trying to
follow the instructions from the Xen wiki, as well as this
https://groups.google.com/g/qubes-devel/c/UzO0BsIfIow/m/C7us11XHAwAJ post,
but I am new to Qubes so I didn't realize that it no longer uses individual
config files for AppVMs. I found this
https://groups.google.com/g/qubes-users/c/K8lfxC8xdp4/m/jGwC-gxnBAAJ
thread, and am now trying to create a custom config file in
/etc/qubes/templates/libvirt/xen/by-name based off of the default xen.xml
file, but I am not sure how to edit the file in a way that would allow
nested virtualization in my windows vm.

A somewhat more recent thread: Re: [qubes-users] Re: [Advanced] Enabling nested virtualization in Qubes/HVM. Editing config files would be the easy part; I think you'd have to recompile Qubes to enable nested virtualization. I used to run Virtualbox on Windows as well, but instead converted my workflows/VMs over to Qubes only. Do you have a specific use case that requires Virtualbox?