I’m currently working on a browser targeting the T-deck in pure Rust. It’s effectively a text mode command line browser good for reading pages with links and nothing else. There just isn’t the ram for anything more. Interestingly, The slowest part is actually SSL connections.
See the other comment for a MITM large browser server: https://news.ycombinator.com/item?id=45446991
To do everything onboard, maybe, just maybe, you could parse basic HTML/CSS and images. But the majority of pages would of course fail anyway without full support for every modern feature.
This seems like it could be useful: https://limpet.net/mbrubeck/2014/08/08/toy-layout-engine-1.h...