> they're all quite niche in terms of intended audience

I wouldn’t say that of GNOME Web.

> I'm not going back to a web without Ublock

I do every day (switching between luakit on a laptop and firefox-mobile-config on a smartphone), and IMO a good /etc/hosts is good enough (edit: luakit can also read the same blocklist format as µBlock, though it ignores cosmetic filters).