macos – How can I remove this type of virus from my MacBook Air? No solution in Google

I don’t know why a have this virus. Recently I was trying update mi MacBook Air to BigSur, but 3 hours later this MessageBox appear to me, I was trying to find solution on Google but I didn’t find it. I trying to install several Antivirus but literally I can’t, perhaps is the virus that don’t allow me do that. At this time I turn off the wifi. Someone knows where can I find that file? What can I do?
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