Atheros Killer Wi-Fi works! But intermittently?

Hi all,

So I've recently did a fresh-install upgrade from Clover-based Catalina to Opencore Big Sur. I have a Tongfang GK5CN6Z which I've equipped with an Atheros Killer AC 1550. I've always used a USB WiFi dongle because this thing was never meant to work with macOS. Booted first time into Big Sur and to my utmost disbelief I had functioning WiFi! Except it was patchy and kept dropping the connection every few minutes. Similar story with Bluetooth, except Bluetooth is a bit more stable - I could use my AirPods Pro to listen to music!

Now I know this thing has no right to even register let alone function but I'd really like to know if there's anything I can do to stabilise this connection?

I am currently using the following related kexts:

AirportBrcmFixup, AirportItlwm-BigSur, BrcmBluetoothInjector, BrcmFirmwareData, BrcmPatchRAM3, IntelBluetoothFirmware, IntelBluetoothInjector, RealtekRTL8111

PS: I put in all these Broadcom kexts because I was planning to swap my Killer for a BCM at some point.

Any help is appreciated!