@heldercervantes Each workspace gets its own separate set of tabs for each window. So, if you have workspace "Test", you can have different tabs in "Test" in each window.
(Remember that to save all opened windows when you close Opera, don't close any of the windows themselves. Click the menu button at the top left of Opera and choose exit. That way, all windows are restored when you start Opera again and the tabs you have for each workspace in each window are restored.)