MacBook Air M1 wifi speed problem when the lid is closed (Working with external monitor connected)

The antenna is in the Display Assembly. So when the Display is open the antennas have a larger surface area and angle to send/receive signals. When the Display is closed, then the surface area and directional ability is reduced.

Hi molinajp,

We understand you're experiencing an issue with the Wi-Fi connection on your Mac. We would recommend the following resources that may help:

Use Wireless Diagnostics on your Mac

If your Mac doesn't connect to the Internet over Wi-Fi

Hope this helps!

Have a great day.

I'm not aware of any way to do that, but I'm not an expert when it comes to some of the more advanced features/options.

A quick search revealed these two options, but I don't know if they will work on newer versions of macOS or Apple hardware, but I have never used either method:

Changing the NVRAM settings (unfortunately requires temporarily disabling SIP and using the command line).

https://apple.stackexchange.com/a/301847

Using a third party app (there may be other apps, this is just an example).

https://apple.stackexchange.com/a/389201