One thing that made me stick to tridactyl is the lack of addon support in qutebrowser, and I don't use that much addons: privacy badger, multi containers (especially this one), cookie auto delete and unlock origin ...
I'm still not sure what exactly Privacy Badger really does under the hood, but I suspect much of it won't be possible with QtWebEngine's API.
Not sure about Cookie Auto Delete - I fear it's not possible to implement either, but I'm not entirely sure, I've always found the QtWebEngine cookie APIs quite confusing so I'd need to take a closer look.
Containers: https://github.com/qutebrowser/qutebrowser/issues/4102
Better adblocker: https://github.com/qutebrowser/qutebrowser/pull/5317
I'm still not sure what exactly Privacy Badger really does under the hood, but I suspect much of it won't be possible with QtWebEngine's API.
Not sure about Cookie Auto Delete - I fear it's not possible to implement either, but I'm not entirely sure, I've always found the QtWebEngine cookie APIs quite confusing so I'd need to take a closer look.