Slow speeds, can't connect to online games, dropped from Xbox parties

I activated a new account last Saturday with the gigabit plan and renting an xfi gateway, and since then, there have been two full days where I was unable to play online games with friends and the wifi connection will generally be very slow (xfinity app taking 45 seconds to load, websites not loading properly, etc.) The NAT type on my xbox would flicker between Open and Strict regularly, or every now and then I would experience Double NAT.

I'm never actually kicked off the internet, so when I try to troubleshoot the connection, it keeps coming back that everything is working as it should, even when the connection is at its worst. I have the gigabit package, and while sometimes it works normally, other times speeds will drop down as low as 30mb.

I have tried unplugging the gateway, resetting it through the app, as well as unplugging and resetting my devices. Nothing works. My xbox/pc are hardwired and I have tried multiple ethernet cables. And the devices connected to wifi (phone, tablet, laptop, ps5) are also experiencing similar issues.

I hope this can be resolved quick. Because telling friends I just can't play on a Friday night is very frustrating.