Nearly constant LAG spikes make gaming impossible

We are so frustrated. We got a new high end gaming PC this September. Unfortunately we don't have the wiring to direct connect modem in my daughter's room. So the tech support recommended I get the Orbi Wifi system and connect her PC to the Satellite. We did that. it worked fine for a while, but was getting some lag spikes. I called into tech support several times and they changed some settings, we reset the Orbi and we are getting almost CONSTANT lag spikes now. It makes gaming IMPOSSIBLE. It's so frustrating. The 3 months is up and now they want me to pay for more support which hasn't helped anyway.

We have had to use our secondary WIFI system which is slower to game. There are no lag spikes at all on that network. Has anyone had this issue? Any help????? I have called support several times and they can't figure it out.

THANK YOU in advance for any help you can provide!!!!