After a search in the NetBSD packages for lightweight web browsers, the winners are: vimb, dillo, luakit and netsurf.
Dillo's new release 3.1.0 still hasn't landed, so no HTTPS there. Luakit is very neat, extremely lightweight, minimal, has vim-like bindings and would be perfect if it weren't for the constant white flashing between each pageload when using a custom, darker CSS. NetSurf is also quite neat, with tab support for heavier sessions.
The winner for me is vimb, which although leaving tabs to the window manager, has vim-like bindings, is pretty minimal and does not cause flashing when switching between pages on a custom darker CSS setting.
Honor mention to Arctic Fox, a Pale Moon clone that hits peak nostalgia with the pre-omnibar Firefox look. No theming, not as lightweight, but going strong at 29.5k commits since 2018.
Just a random fox from my photos. Upgraded icy.arcticfluff.eu to gotofox gotosocial latest release. To see if everything works, here's an arctic fluff. :blobfoxarcticsnug: