How to modify macOS BigSur system sounds?

I recently updated to macOS BigSur and discovered the sounds are awful!

How can I replace them with the old ones?

I know they are in /System/Library/Components/CoreAudio.component but I can't replace them.
How can I force to replace them?
What do I have as options?


Solution 1:

You can add your own sounds to ~/Library/Sounds, the one in your Home folder, and they will then appear in System Preferences > Sounds > Sound Effects, and in the Mail.app's Preferences.

Apple is making modification of the system files increasingly difficult, for security.