On my laptop only, I can only game online using ethernet. Not wifi. Tablet plays same games fine. Please help

I just moved into a new apartment and got an xb8 gateway. Prior, my roommate and I had the same gateway and I had absolutely NO issues gaming. Now, with this new gateway (new account, the other xb8 was his), I can only use my PC to game using ethernet. On ethernet the games all run perfectly. Otherwise, on wifi, I get network connection errors for every online game I've tried to log into. Either that or the game will allow me to log in and play for 30 sec before the network connection issues start and then the internet drops with "no internet". Keep in mind, I'm RIGHT in front of the router as I put it in the middle of the living room floor to test. It's been like this since day one, end of May. 

This is only on my PC. My tablet plays the same games just fine over the same wifi.

Port forwarding didn't help

switching from 3 to wpa2 didn't help. 

rebooting the gateway didn't help. 

restarting the PC, obviously... 

Everything was fine prior to me moving and starting up a new account. I have the same speed we had just a few weeks ago, same router, etc. Shoot, prior to that, I lived with someone who had an older xfinity router and that also worked perfectly. This is the first time in 2 years or so of xfinity and this ASUS ROG laptop that I've ran into this issue.

If you can help, please do. I'm absolutely baffled as I'm using the exact setup we had previously, just with less devices on the network.  He wasn't a gamer at all so he didn't do anything special with his, settings wise.