Wifi not working after BigSur update!

Hello,

I am also a Macbook Air 2017 user. Whenever I do the BigSur update, I am unable to use Wifi properly from then on.Although my distance to the modem is maybe 10 meters, my internet is not receiving properly and I am constantly experiencing disconnections.Also, the situation has gotten worse with the 11.2 release.

Thinking it might be a hardware issue I took it to Apple and they replaced the wifi card as well. But after BigSur update, the result is still the same. 

Please solution! :/
Wifi not working after BigSur update!
 
 
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