@Techno-Kaj
This procedure will revert:
Via Settings, Enable Widgets (opera://settings/widgets_settings)
Open the speed dial
Open the widgets menu on the speed dial (its at the top right)
There should be a bar on the top asking feedback about the new UI
Next in it, click on the back button [icon of backspace key]
There will be a prompt, optionally give feedback
Click on "revert and restart"
Let the browser restart with the old UI