VERY Slow Wifi Broadcom Driver 7.77.119 Macbook 2017 Windows 10

Hi

I have a Macbook A1534 with the Broadcom 802.11ac adapter. Boot Camp install of Windows 10 Pro. When running a speedtest with Ookla the download starts strong then almost immediately drops down to a choppy 5mbit, then falls further down to 1. Real world downloads see similar performance.

Why is my wifi performance in Windows so bad? It's perfect in MacOS.

Things I've tried from other forum posts:

Turn bluetooth off

Rollback to 7.35 driver version

Mess around with Advanced driver settins

Run Apple Update tool and Windows Update tool

Run TCP Optimizer

I only got the laptop a few days ago and did clean installs of everything after wiping the drive.

Please help.