Wifi Issue persists on MacOS Catalina - MacBook 2017

HI Community,

I have recently (unfortunately) updated my MacBook to Catalina and now have Wifi Issues which unfortunately infect my complete system and make the computer unusable.

I connect to my network which seems to be successful but do not have internet connection. However, the system thinks I do and seems to tell all other apps that internet is available. These seem to try to connect (e.g. iCloud apple ID) in the background but are unsuccessful.

I have tried for the last 2 hours to solve this issue by:

• Get latest updates (yes, is up to date)
• setting up a new location as stated here https://macreports.com/mac-catalina-wi-fi-problems-fix/ and in another thread here in the forum. It does not work
• I also do have this problem in safe mode
• I tried to reset the network setting by removing some files as stated here: https://www.igeeksblog.com/how-to-fix-wi-fi-issues-on-mac/
• I also adapted DNS settings, kicked out the network completely, manually rejoined, set the Mac Adress Hardware setting to manual --> nothing yields any result

What I find very interesting and haven't read anywhere else:

• Deactivating Wifi takes up to 3 minutes
• Activating Wifi takes up to 3 minutes
• Opening network preferences takes up to 3 minutes, switching to advanced takes up to one minute, changing tab in advanced dialog takes up to one minute

--> System is incredibly slow

I am really challenged by this and can't believe that apple seems to not have fixed Wifi issues.

Can please somebody help?

Thanks