@pojntfx @jimmac this, and the lack of ability to handle large amounts of tabs (both performance and UX) is what's keeping me from using Epiphany for more than just standalone web apps and occasional testing. I don't have the luxury to limit myself to a dozen tabs.
For UX, what I want is:
* Workspaces: https://gitlab.gnome.org/GNOME/epiphany/-/issues/1835
* Vertical tabs: https://gitlab.gnome.org/Teams/Design/whiteboards/-/issues/44
In terms of performance:
* Automatic unloading: https://bugs.webkit.org/show_bug.cgi?id=291369
* https://gitlab.gnome.org/GNOME/epiphany/-/issues/1454
* https://gitlab.gnome.org/GNOME/epiphany/-/issues/2796

The current posterchild of this feature is the "Simple Tab Groups" Firefox extension, the most reliable and well-rounded successor to the defunct...