What does HackerNews think of otter-browser?
Otter Browser aims to recreate the best aspects of the classic Opera (12.x) UI using Qt5
https://github.com/OtterBrowser/otter-browser
Ungoogled Chromium
The Android version https://github.com/macchrome/droidchrome/releases comes with customizable adblock filters e.g. easylist, I don't care about cookies, EasyPrivacy etc. that I'm no longer forced to put up with Firefox's jank just for some decent adblocking on my phone anymore.
Yes very annoying. They dont have to bring Safari on Windows, but at least WebKit on Windows would be nice for testing. In the mean time, Otter for Cross Platform Browser [1], or you could do Gnome Web with Windows WSL2.
Ubuntu (mainly phone, coming soon to desktop) has these:
https://launchpad.net/webbrowser-app https://launchpad.net/oxide
It's based on Chromium/Blink.
And Qt itself switched from QtWebkit to Chromium with QtWebEngine - https://wiki.qt.io/QtWebEngine
Not quite the same category, but if anyone is interested in a modern Opera-alike browser check out Otter : https://github.com/OtterBrowser/otter-browser
Their main website isn't loading for me at the moment (edit: must have been the network I was on, I'm connected to a different one now and it loads fine), but you can get a good deal of info from the Github. It's under active development and while I wouldn't replace Firefox with it yet I may very well at some point.