Reduce bandwidth
You can reduce RDP bandwidth usage with following possibility :
Turn off desktop background and animations etc. on the RDP clients tab "Experience" before connecting.
And turn off desktop wallpaper etc. in the users session. (plain blue or black is best as desktop background)
This can also be done on server-side -> open Group Policy Editor
Navigate to Computer Configuration / Administrative Templates/ Windows Components/ Remote Desktop Services/ Remote Desktop Session Host/Remote Session Environment
Here you can enable "Enforce Removal of Remote Desktop Wallpaper", etc.