Here like Marko85 when someone started to fix this bug? I have already done all the tutorials to repair wif-fi Big Sur from the internet.

Same thing here with my (iMac (Retina 5K, 27-inch, 2017) Wi-fi started to fail and suddenly stopped once I did all tutorials on the intenet and nothing worked and finally I reinstalled Catalina and wi-fi is still dead. After I moved to BigSur it's been hell WI-FI and Bluetoth have never been the same if you count the time you spend looking for solutions as I figured this update (11.4) would solve that.