I still want to reinvent the web with a hypertext document reader that doesn't include the kitchen sink. I suppose with LLMs these days this is actually an achievable prototype.
There are plenty of crippled web browsers out there. Heck, on iOS, it's the default.
nyxt? helium? midori?
There are hundreds of browsers these days, you shouldn't have a hard time finding one that fits your needs.
Conversely, a web app platform that includes all the primitives that are needed to build a decent web app (as opposed to bring your own everything/building castles from grains of sand model) would be nice. It doesn't necessarily have to be a browser, though.