When MacBook Air is connected to the internet it drastically slows down the wifi for other devices
The wifi on my MacBook Air (13-inch, Early 2014) works perfectly fine but other devices that are connected to the same wifi will slow down and get very glitchy periodically. This will stop video streaming on other devices and will cause my partner's game to glitch really badly on his PC that has its own ethernet cable. This issue only occurs when my MacBook Air is on and connected to the wifi.
I have stopped downloading any files whatsoever, removed my iCloud, deleted any possible applications that can be running in the background, enabled the 'Cache' tab in Content Sharing (Seen in the Activity Monitor), disabled automatic software updates, turned off My Photo Stream, and anything else I could think of to reduce bandwidth usage.
Under the Network tab in Activity Monitor there are some processes I don't fully understand - is there something I should be looking for?
What else can I do to fix this problem?
MacBook Air 13", macOS 10.15