Unstable Download Speeds

Hello everyone,

I'm currently experiencing unstable download speeds with my current setup. Right now I'm using a Nighthawk AC1900 USB adapter that's connected to my AC1750 Wi-Fi Mesh Extender which is repeating a signal from my Nighthawk C7000v2 Cable Router. My router is upstairs, while my extender and desktop computer are downstairs.

My desktop specs: Intel i7-4790k, Windows 10 (version 2004, build 19041.329)

I noticed recently that I haven't been getting a consistent MB/s from the games I've been attemping to download. Rates will jump from 1.2MB/s to >7MB/s seemingly every second and it's taking a long time to download anything really. I'm just curious if there's a setting in either my extender Wi-Fi options or router options that I can change to help get more stable download speeds. I really don't have much connected to this extender and my computer and mobile device are the only things that are constantly connected to it. All the firmware on each product is up to date as well.

I currently have "One Wi-Fi Name" enabled and "Smart Switch" disabled on my extender (if this is any helpful information..) I'm assuming that my issue is my extender or possibly my cable connection but I've left an attachment below of my extender status page.

Any help would be greatly appreciated.