I would try hosting the HA database on your Win10 machine before upgrading hardware, yuo may find the Database IO is the bottleneck and not CPU.
How did you copy the snapshot to the new Hassio setup?
Install the SSH or Samba addon.
If I remember correctly, the samba add on. Ps also worth looking at the Google drive backup add on. That makes it even easier
With the Visual Studio add-on it’s even drag and drop!
Do you mean drag and drop yaml files not the snapshot file?
You can drag and drop anything you like. Even the snapshot files
Just open the backup folder and drop it in.