macOS Big Sur is Big mistake

Revert your Mac to a previous macOS version

important - if this computer originally came with Big Sur - one can not downgrade to a previous OS. Those are Apple Rules.

Did you make a back up of your system drive before upgrading?

Go to the Apple Menu > About this Mac > System Report and please post what the exact model name and Model Identifier is.

Do not post your serial number.

MtD