The in-browser Lovelace UI Editor is great for editing panels, but there doesn’t seem to be a “nice” way to change the order that Views/Tabs are shown.
You can do it by editing the Raw config editor, and cut’n’pasting the full View, but this is cumbersome and not without risk of breaking the whole config.
A simple implementation would be to add a field to the View Settings to select which other View the current View is Before/After.
More advanced would be to allow drag’n’drop of the Views when in Edit mode.