Slow WiFi internet speed on M2 Pro

Poisoning Internet performance:

By far the easiest way to cause poor performance, instability, overheating and crashing is to install ANY third-party speeder-uppers, Cleaners, Optimizers, or Virus scanners. or a VPN that you installed yourself.

The idea that a third party, with no special knowledge of the inner workings of MacOS, can somehow find a simple way to protect your computer — that is not already being done by MacOS itself — suggests that the MacOS developers are somehow "holding out on you". That is absurd.

You should remove any and all (other than Apple built-in) virus scanners, speeder uppers, optimizers, cleaners, App deleters or VPN packages you installed yourself, or anything of that ilk.

Third-party file Sync-ers such as DropBox, BackBlaze, OneDrive, or GoogleDrive can ruin performance, but are not inherently dangerous.

Effective defenses against malware and ot… - Apple Community

Effective defenses against malware and ot… - Apple Community

To determine whether added software is the problem, run in Safe Mode, where no third-party items are loaded.

"Works in Safe Mode, Fails in regular mode" implies, "it's something you added."

to look at possible Hardware issues, hold down the Option key while you click on the Wi-Fi Icon on the menuBar. You get a snapshot similar to this older one. Photograph, Screenshot, or Transcribe the values back here and Readers can help you analyze your "network neighborhood".

...

you are using the 5GHz band and have established a connection on channel 40 at 80 MHz wide. Over that, using your excellent raw signal RSSI of -45 (which suggests you are very close to your Router) you have been able to maintain a connection that supports a Transmit rate of 866 M bits/sec and uses patterns with 256 patterns per signaling interval over two antennas.

This suggests no hardware issues, low interference, good signal.

The difference between your measured 12.17 and actual 866 can not be explained by networking issues.

what nominal speed does your Internet service provider give you?

are you running a VPN you installed yourself?

are you running any third-party file sync-ers like Dropbox, BackBlaze, OneDrive?

if you restart into Safe mode, is your internet speed higher?