Apple has updated the appearance of Safari in the third developer beta of macOS Monterey, making the tab bar more comparable to the existing tab bar in macOS Big Sur.
The previous Safari design did away with the specific URL and search interface in favor of enabling navigation input to be entered into any tab. To reduce the amount of space taken up at the top of a Safari window, all tabs were positioned towards the top of the display.
In macOS 12 Developer Beta 3, the tabs are arranged underneath a dedicated URL/search bar at the top of the Safari window. When you click on a tab, it becomes the current window, and dragging tabs for reordering or opening in a new window is easier.
When updating to macOS Monterey beta 3, the new and distinct tab bar is enabled by default, but Apple has added an option to restore to the original Monterey design. You can use the old look if you go to View and turn off “Show Separate Tab Bar.”
Apple also introduced Universal Control settings to the Advanced tab of the Display preferences pane, but the feature does not appear to be operating yet.