Maybe I can be of assistance, I haven't seen this issue personally on my windows vm
xo vm config
- video RAM 8MiB
- VGA on
test
today using Remmina from Linux executing this command in the VM i get:
Get-WmiObject win32_videocontroller | select caption,videomodedescription
result:
Caption VideoModeDescription
------- --------------------
Microsoft Remote Display Adapter 2508 x 1302 x 4294967296 colors
Microsoft Basic Display Adapter 1024 x 768 x 4294967296 colors
I won't say for certain but i think the virtual RDP screen is the first one and the "VGA" console is the second one.
How are you checking your resolution inside windows RDP?