To add to this a little bit. There is deeper host side integration for these applications and the VM’s are virtual address backed (the guest vm’s memory is represented as a process on the host), which adds more opportunities to free up physical memory. The windows sandbox architecture page covers some of this.

https://learn.microsoft.com/en-us/windows/security/threat-pr...

Also WSL2, if I recall correctly, has a relatively minimal base OS with a custom init binary.

I would say if you’re looking to use Host Compute Service, your best option would be to look at the way https://github.com/microsoft/hcsshim initializes containers.