Erratic Wifi speed with macOS Big Sur 11.2.3

I setup NextDNS on my 2015 MacBook Pro on February 19, 2021. At the time I was running Big Sur 11.2.1. To confirm my wifi speed after setting up NextDNS I ran a speedtest and got 200 mbps which is what our Optimum subscription is for.

By the time I got around to updating to 11.2.2 which was released February 25th 11.2.3 was out. I updated to 11.2.3 shortly after its release on March 8th. Since updating to 11.2.3 my wifi speeds have been erratic. The fastest I’ve been able to get is 130 mbps and the lowest has been 29 mbps. average On average it is around 35 to 50 mbps. I have gone through all the normal procedures for troubleshooting slow wifi to no avail.

Speedtest on my iPhone and iPad is consistently 200 to 220 mbps so I know the problem isn’t with my network.

I blame the problem on Big Sur. Has anyone else experienced this?

I have been having network speed erratic issues as well with both of my Macs. I thought it was just some network interference (low signal) in my office, but it works perfectly fine on all my iOS devices and everything else in my house. You may be on to something here. :confused:

I have gigabit service on fiber and an Eero mesh. The Eero hub ten feet away from me is getting 950/950 down/up speed. Or so the Eero app tells me. My MBP on 11.2.3, ten feet away from that Eero, is only getting 95/30 down/up speed when running WiFi.

The speed deteriorated significantly under Big Sur. I don’t think the issue is with Eero’s mesh, since I am literally sitting on top of it.