Opera Mini is one awesome browser for such connections. Average page sizes were around __20 KiB__ (They use some compression proxy). No Javascript was loaded. (Simple JS tasks were delegated to server side. I guess with some optimizations they could save on those full page reloads, but maybe it was computationally expensive for those phones).
There was a vibrant ecosystem for those phones. Till this day, those websites that host pirated music from Indian movies work with simplest of WWW browsers.
That's nostalgia. I remember a Modded version of opera mini which had tonnes of other features that worked on those phones with 4-8 MiB of memory (I don't know exact specs though, they were not mentioned for those phones).
Even today, with my paranoid no-js no-web-fonts browsing (UBlock origin), there are parts of web that are efficient. Hacker news or i.reddit.com, for example.