Mac Mini (m2) wifi speed link fluctation

The Mac mini's wireless antenna is built into the bottom cover which puts the Wi-fi and Bluetooth reception at a disadvantage compared to other devices. On top of that, poorly shielded high speed USB cables, drives and displays in and around the Mac mini can cause interference and poor wireless reception.

see > Resolve Wi-Fi and Bluetooth issues caused by wireless interference - Apple Support

Some possible solutions for achieving better wireless reception include:

1) rearranging the Mac mini setup, so that there are no USB cable and devices in-between the Router and Mac mini.

2) moving the Router and Mac mini closer to each other, using a Wi-Fi extender or using Ethernet if possible.

3) placing the Mac mini on it side in a side-stand with the bottom facing in the direction of the Router.

The Wi-Fi radio on the M2 Mac mini Pro (mine) hunts incessantly and the connection speed between the mini and the router is continuously changing up and down. I have turned the mini on its side with the bottom facing the Wi-Fi 6 router that is 20 feet away on the other side of drywall.

I happen to have a Wi-Fi 6E cellular 5G hotspot on my Desktop primarily for power outages. The same variable connection rates occur when using this hotspot five feet from the mini, and the primary difference is that the connection rates fluctuate between 1200Mbps and 2200 Mbps.

Nothing can be done about this Wi Fi fluctuation in current Apple products and the bigger story is the latency and Internet connection speeds you experience.

I see that you are using the 5GHz band, which can have problems penetrating solid objects.

What happens when you switch the Mac mini to the 2.4GHz band....?

Apple may have done the M2 mini engineered just fine and the third-party Wi-Fi chip may be doing what it was designed to do — though not what we want it to be doing. If the chip is designed to process Wi-Fi signals one way, and the router is transmitting them differently, this too could cause the Wi-Fi chip to "hunt" for signal strength.