Trying to divide bandwidth appropriately to lower ping response.

I have two WAN links. 50x50 fiber and 100x10 coax. It's setup on a active/active with 3 to 1 weight ratio wan link setup.

When our cloud backups occur on the individual desktops, although they are throttled to 64kb upload each, there are 10-20 of these desktops doing this at the same time. It drags the coax connection down and makes the ping keep a constant 200-300ms response with minimal packet loss. Our ISP confirms that everything looks good on there end. So I can only figure that we need to put in some form of traffic shaping policy to stop this so that people can work during the day? Can someone help me achieve this goal? Still learning these XG's especially traffic shaping.

Thanks.