Xbox Gaming Connection Skipping

I got my T-Mobile 5g gateway back in March and gaming on my Xbox one was great, I had no issues at all with browsing the internet, or running games like Fortnite and overwatch, last weekend, 9/27, I noticed while gaming that my screen would freeze while in game and I'd disconnect/lose connection moments later and that has been the same outcome everytime I try to play games , I even tried gaming on my laptop and it was the same outcome, disconnecting & losing connection. I called customer support and they told me to use a ethernet cable while gaming & to setup a new network for gaming only and that should make it more smooth, but I'm still having the same issues with a ethernet cable connected to my laptop/xbox for gaming….  I'm not sure what I'll do if this continues. i don't get how everything runs well for 7 months and all of a sudden it can't handle gaming now, but browsing the internet & watching videos runs just fine.