Luckily, I noticed the issue does not persist if the power cable usb-c is plugged into that port. (Note: the wifi source is located on the right of the computer, so maybe it would be the left side if your wifi source is located on the left of the computer.) If I have it plugged into my usb hub or monitor from that port, my wifi takes a turn for the worse. By using google speed test and having one cable plugged in at a time, I was able to determine that my front right USB port was the problem. I was having this same issue but was able to come up with a work around.

The good news is the power of the good devices is low and the inverse power law prevents a USB 3.0 device from interfering with 2.4 GHz signal across the room, but for the computer connected, they are simply too close in most cases to rely on both 2.4 GHz WiFi and USB 3 together.

You'll also need a way to measure / triage / eliminate faulty or poorly designed USB 3 devices - they will ruin many people's day with interference. If you use a lot of the newer adapters, you'll want to be sure you have a good 5 GHz wireless network running. Unless you can somehow separate the devices physically, even with ideal 2.4 GHz radio conditions of low noise and good signal, with properly designed, properly assembled and correctly operating USB 3.x hardware, they can interfere significantly with the older WiFi standard channels in the 2.4 GHz range. Great shielding can help as can drivers that literally turn off the USB 3.0 signal periodically to give the WiFi a better (slim) chance to get some traffic through. Least to blame is companies that don’t support good hardware that can have failures. Some engineer somewhere designed the hardware and blame government for not checking the engineer was licensed or clawing back licenses when people ship garbage hardware. So now the blame shifts engineers for working on products they know can’t be reliable and doing what management asks. For most people, understanding that interference can happen helps them find practical remedies. Now, if the Mac works without any accessories, you have to blame the accessory or purchaser of the accessory of you insist on a blame centric worldview. The inverse square power law means that a signal that is very weak a few feet away can cause severe interference right next to the Bluetooth and WiFi disrupting the 2.4 GHz signal.

Is there a wireless usb hub for macbook