Wi-Fi download and upload rates, general internet connection not matching other devices in my house, internet cuts out on occasion for a few seconds

This whole problem started a few months ago (I don't entirely remember when but it suddenly showed up one day) where specifically my laptop began experiencing worse internet than what I am paying for. I know it's not a router problem because I called up my provider and they said there wasn't an issue on their side.

My device and the accompanying peripherals:

* MSI GS76 Stealth running Windows 10 * PLANAR external monitor * Microsoft wireless multimedia keyboard 1.1 w/ USB-connected dongle * Razer Basilisk X Hyperspeed mouse using bluetooth feature * Corsair HS80 headset using bluetooth feature * A 7-port USB 3.0 hub. * Killer WIFI 6E Wireless Network Adapter

The problem is:

* Substantially lower upload and download rates through my internet connection (originally for example, I'd download 30 megabytes a second (I recall downloading 20-gigabyte games in only an hour or less) on Steam and now it shows at most 3.1mbps or so. Also slower network rates on Steam.) * Wi-Fi disconnects and reconnects when I'm playing online games, bars on the Wi-Fi icon on my taskbar show large fluctuations when I have 3 or more tabs on a browser open or if I have both Discord and an online game/internet browser open. The length of the cutout is up to 10 seconds or so.

Info of Note:

* My AT&T plan has a general download speed of 280mbps. * I have an Orbi router using 5 gigahertz ethernet connected to an AT&T gateway. * Ookla shows a download speed of 30mbps and an upload of 10mbps.

What I've already tried:

* Reinstallation of my wifi driver and my bluetooth driver. This did not work. * Clearing of my network cache/network settings with no meaningful results. * Resetting my router and my gateway. No change. * Changing to a different ethernet port connecting my router and gateway. No change.

I must repeat that this happens with my laptop ONLY.