Greetings, I am also a Macbook Air 2017 user. Whenever I did the BigSur update, I cannot use Wifi properly from that moment on. Although my distance to the modem is maybe 10 meters, my internet does not receive properly and I constantly experience disconnections. Also the situation worsened with the 11.2 release. Thinking it might be a hardware problem, I took it to Apple and they changed the wifi card too. But the result is still the same after the BigSur update. Please solution ..