Lynx

Maybe Pale Moon, Basilisk or maybe some WebKit-based browser like LuaKit or similar.

Then better Chawan.

What is Chawan ??

It's a TUI browser that can render really better any webpage, and can also use the Kitty Graphics Protocol to be able to render them pixel-perfect.

With those specs nothing will be fast. Except Lynx or w3m - which are not really usefull for modern browsing.

If you can, at least upgrade your memory and disk to ssd. You cam get second hand stuff for pretty cheap.
However if you cannot do that I would first make sure you get your OS as lightweight as possible to free as much of your resources for browsing. Arch is a good choice. I would also use LXCE for your desktop environment. Or even no desktop environment at all and just boot to browser.

Then you should use modern browser with as little bloat as possible. You have two realistic choices: chromium fork (like brave) or firefox fork (like librewolf or mull browser).
Make sure you open setting and disable all the things you do not need. You shluld also google what are some more advanced things you could disable.
Make sure you install ublock origin extention and open its setting and set it to block everything that sites do not need to run (like ads etc...)

I think noscript or umatrix extention would also improve your experience. Since lots of websites do not need to run code in background.

Make sure you do not install extentions you do not need.

If for some reason you can afford to own raspberry pi or non-provider router while you can afford to buy some extra ram:
Offload blocking to your router or pihole. Maybe you will have to upgrade your router to openwrt if it is supported.
If your internet speed is also slow:
Setup a proxy that would cache all websites you visit. So they will load faster the next time.

You can also browse some stuff offline. Wikipedia can be downloaded and browsed locally. There are apps for that. Apps that are way more lightweight than a browser.

I hope all this helps you somehow.