I'll skip the Opera part of the question since I don't use it these days, and since you're not open to FireFox plugins, I can suggest Tabs Outliner (http://tabsoutliner.com) from the Chrome web store. I'd assume it'll run well with macOS & your Chromium-compatible browser of choice too.
It would not give you a native UI of vertical tabs, nor might it directly satisfy your personal preference of vertical tabs (its implementation gives you a vertical view of tabs, among other features), but as a vertical tabs fan myself I've been using it happily for years now.
A few vertical tabs related features listed in their plugin description:
☀ Complete Overview of all your open and saved tabs and windows, along with custom added notes and marks.
☀ Flexible and fully editable by Drag and Drop Tree - everything can be easily organized in logical hierarchies and delimited groups; unlike in other similar tools every node can be a parent for any other node, all items can be freely reordered to specify priority or importance. And all of this can be done not only with somewhere saved links - but with open tabs and windows!
☀ Tree Style Tab feature - those who remember famous Firefox plugin with the same name immediately recognize inspired by it very useful way to relate tabs to one another. This feature relates newly opened tabs to the tab from which they were opened, which automatically builds strong context for all items and nicely visualize tabs relations.
