M1 Max MacBook Pro very slow internet response

Yeah, I was kinda just venting about the hardware. But this is a new machine, configured from the perfectly performing old one by Time Machine 10 days ago, and was misbehaving in this respect from the very start. I'm puzzled how it might have picked up interfering software almost instantly. Or perhaps it's something that was carried over but wasn't affecting the old machine. And now, half an hour later, it's performing quite normally. This intermittency is the usual pattern.

I'm not using a virus scanner. I'll restart in Safe Mode next time this occurs.

Here's a couple of screen shots. The additional networks belong to neighbors, except for the Arris, which might be generated by our cable modem. It's in the basement and across the house from the laptop, so it's not strong.

I do appreciate your helping me out!

I'll try both of your suggestions the next time I encounter the problem, which may well be the next time I awaken the MacBook from sleep. Something that I failed to add in my original post is that after a seemingly random length of time, minutes to an hour or more, the wifi/internet response becomes normal.

I don't have much hope for Network Diagnostics, as the other Macs and devices on the same network, including an HP Windows machine, have no difficulties.

The problem got to the point where not only was internet service slow and erratic, but the laptop would not print over a wifi-connected printer and began to drop connections with the network – despite being three feet from one node of my home mesh network. Meanwhile, in our home an iMac, a different MacBook, a Windows laptop, four iPads, two iPhones, a HomePod and a cluster of Sonos components continued to work with the network just fine, and the ones that access the internet continued to do so at normal speeds.

In desperation, I reinstalled Monterey. The progress bar told me it would take 11+ hours, suggesting very slow data rates. I then connected the MacBook to my cable modem with an Ethernet cable and the time soon dropped to 5+ hours. Two hours later I came back and the computer was ready to go. These behaviors convinced me that the problem was with the MacBook, probably with connecting to wifi but perhaps more fundamentally with handling data through whatever port interfaces with a network, either wifi or Ethernet.

Now the problem seems to be no more. Web pages load immediately and fully. Emails open instantly. It appears that reinstalling the OS has solved the problem.

Thank you for the suggestions about the network, but the problem seems to have lain elsewhere.

Well, I was wrong. This morning the laptop dropped the wifi connection, wouldn't reconnect until I commanded it to, loads web pages glacially slowly despite all three bars of signal strength, and needed at least four minutes to get to this page once I typed "discussions" in the address bar.

I can only conclude that the hardware is defective. I'm going to take it to the Apple Store, if they're physically open, and failing resolution, will avail myself of the satisfaction guarantee of replacement or refund...if there is one. I have never done this with an Apple product in 36 years of being a user of countless Apple devices, but this is ridiculous. My brand-new MacBook is effectively unusable as an internet portal and therefore useless to me.

I restarted in Safe Mode, and the MacBook is flying through the web pages. Whether that's the erratic behavior I've been experiencing, or due to excluding something with Safe Mode, I can't tell. Need to do this more often for an adequate sample size.

My home system is a Linksys Velop mesh network that operates on 3 bands. I'll dive into its app to see if I can command it to 5GHz. Now I'm wondering why I don't see my router's 5GHz network on the list. I've seen multiple networks from my home router listed in the past, as Guest and on both bands, but not sure I have since I installed the Linksys.

Thanks again for the analysis and suggestions.

At first it looked like Safe Mode avoided the problem, but after alternating back and forth between it and normal mode, it was not entirely clear that slow response was never seen in Safe Mode, or as before, not always seen in normal mode.

Then I twiddled with my mesh network in the Linksys app and now normal mode seems to be humming along, I verified that the MacBook is now on the 5GHz network, with S/N about 55 db. Thanks for teaching me how to evaluate this.

Is there a way to show what non-Apple extensions Safe Mode does not install, in case I have to more sleuthing?

Just a bit! Up from 130Mb/s to 866. Normal performance continues without resort to Safe Mode.

Thanks again for helping me sort this out. Nothing in my experience would lead me to believe that the lousy performance I was experiencing could come solely from being on an otherwise normally performing 2.4GHz network, but forcing the router to switch to 5GHz was the point at which the problem vanished, so...