It's something that has been bothering many Opera users, to be honest. Recently, I was amazed by the convenience of tab division in Vivaldi, but I was disappointed with some other features, so I switched back to Opera hoping to find something similar here. I tried using the Tile Tabs extension, but it didn't quite please me. I would like all the tabs to be displayed at the top, just like Vivaldi does. A temporary solution was using the Web Panel in the sidebar, fixing it and dividing it with the other tabs.
I really miss a tab division feature without having to open another instance of Opera. I believe this is a fundamental feature for modern browsers, especially with the increasing screen sizes.