When you save the state of a Hyper-V VM a VMRS file is created. From what I can gather (!) this file contains, amongst other state information, a full uncompressed memory dump of the VM.
I like that you can use volatility directly on the .vmem files that VMware produces when saving the state, and wish the same could be done with Hyper-V save states.
I found this which may be helpful for reference, but it appears to be using a Microsoft DLL.
https://github.com/ufrisk/LeechCore-plugins/tree/master?tab=readme-ov-file#leechcore_device_hvsavedstate