Opera used to be a fantastic web browser, with a custom high-performance Presto rendering engine and features like tabbed windows that didn't show up in competing browsers until years later. However, the modern Opera browser is a shadow of its former self, reliant on chasing trends and meme advertising to
Fair, that is pretty awesome feature, especially for the tab sprawl in this day and age.
I (obviously) use Firefox, and I had the same problem, and found the “Tree Style Tab” extension solves the same problem for me, however it does it in a very different way.
Instead of having your tabs along the top of the window, your tabs are kept in a sidebar, and vertically. Opening new tabs from an already open page makes the new tabs nest under the original tab. You can collapse and expand whole trees of tabs, and move them around should you need to.
It also integrates nicely with the “Container Tabs” putting a colored band next to the tabs belonging to each container.
The tabs being vertical also means that you can always read the titles of the tabs, they don’t get “squished”.
It does cost a chunk of screen real estate, but for me the organization is worth it.
BTW: The extension doesn’t itself hide the tabbar at the top of the window, but that can be hidden with a relatively easy modification to a file.