Bluetooth Adapter slowing Wifi Connection on Ubuntu 18.04.1

I have recently downloaded Ubuntu 18.04 on a computer I built, and I installed a bluetooth adapter in order to access the internet. However, upon connecting to my Asus BT400 bluetooth adapter, I have experienced a major reduction in my internet speed compared to my Windows 10 laptop. I have disabled bluetooth coexistence with Wifi, but my internet speeds are still incredibly slow.

Any ideas on how to improve these internet speeds?

Try

1. Changing the antenna used for wifi.
2. The channel used by the router (the method for this depends on the router).

Notes:

1. Why do you need "a bluetooth adapter in order to access the internet"?
2. So you: 1) had a wifi working at a reasonable speed, 2) added bluetooth and wifi speed slowed down, 3) disabled bluetooth and wifi is still slow? If not, what is the sequence you tested?

Related:

1. Wifi and Bluetooth not working simultaneously
2. https://www.codejourney.net/2017/04/wifi-and-bluetooth-interference-diagnosing-and-fixing/