Peter I'm looking into implementing JS in a smaller browser. I must admit that this task is probably to hard for me, but I try it, and it can't hurt even if I fail, and I might learn something by trying.
You should try asking the people behind other render engines, they might be able to help you on that task. And be sure to share the result of your effort, I'll be interested even in the fails :)
And some people noticed that the current web is a too large beast. So they invented Gemini.
I'm not that sure about gemini tbh. No embedding is really a huge backward step. I understand the motivations, but to me the stuff is pretty bad.
Let me just make this explicit: Gemini, unlike the web, is a protocol + a format. The web is built over several standards, which is certainly a part of the problems it suffers, but nothing prevents one to use http or html outside of the web, and those points make it rather strong. Gemini is (and will stay) weak because of the lack of flexibility it offers.
Again, I know the reasons behind that choice, but I simply say I'm doubtful. It just feels like a passeist thing to me, even if I am a rather minimalist person. Still, some ideas would be great if adopted by the web, like the lack of central authority, the so called "chain of trust". But, we're going out of topic now :)