I tried Vivaldi, don't really even see a difference between the tab drawers. Except Vivaldi does have bigger tab previews and buttons which feel easier to press. The lack of tab reordering in private mode definitely seems like an oversight.
Tabs in tablet mode would definitely be cool too, but I don't know what the experience is like on tablet.
On Android you can just long press links to open private tab or new tab. Seeing Vivaldi's feature bloat if a bottom bar with infrequently used buttons that blocks viewing space, and a completely unnecessary tab bar on mobile that wastes space, feels like an ancient outdated design from 5+ years ago.
That's kind of Vivaldi's design though, ridiculous feature bloat and cluttering the screen with useless crap instead of trying to preserve screen space when these single press buttons can easily be moved to gestures or condensed. You know, like modern UX design. Like a third of my screen is just gone because of of redundant buttons and UI. Reminds me of Internet Explorer days with Yahoo toolbar.