Use Apple's recovery application first before trying anything. It could be as an app in the Application directory, or you can gain access by holding down the option's key at boot up, just after the apple chime.I will try to make a clean reinstall of Big Sur. Any hints on how to do it?
Use macOS Recovery on an Intel-based Mac
Learn how to use macOS Recovery on an Intel-based Mac.
support.apple.com
To create a boot drive.
How to clean install macOS on your Mac
Speed up your Mac and rid it of problems by reformatting it before doing a clean install of macOS Sonoma.
www.macworld.co.uk
NOTE: Make sure you find out everything on what to do if things go wrong.