How to Disable Tab Preview in Safari MacOS Big Sur

You can disable tab previews in debug menu.

Allow access to Full Disk for Terminal

Go to Settings > Security & Privacy > Privacy

How to Disable Tab Preview in Safari MacOS Big Sur

Restart the Mac

Type in Terminal

defaults write com.apple.Safari IncludeInternalDebugMenu 1

How to Disable Tab Preview in Safari MacOS Big Sur

and Launch Safari

Unselect Show Tab Preview on Hover

In Tab Features > Show Tab Preview on Hover remove the check mark

How to Disable Tab Preview in Safari MacOS Big Sur

To hide Debug menu type in Terminal

How to Disable Tab Preview in Safari MacOS Big Sur