Datapoint: During the pandemic, I had to use an old 2004 Powerbook G4 12" (256 MB RAM, OS X Leopard). Everything sort of worked and was even reasonably snappy. But open one website, and the machine went down. Unusable. Even if, indeed, I just wanted to read or look up a few kB of text. So painful.
One tool I've found useful in low-power/low-bandwidth situations is the Lynx web browser [1]. Used to be installed by default in most Linux distributions but I think that's probably not the case anymore. Wikipedia says its also available on OSX and Windows.
Chawan is nice
If only there was browser-as-a-service. That would load the pages over it's fast connection and show them to you.
I feel like there already was one, on HN a few years ago. If I remember right, they were hoping to charge $20/month.
Edit: Ah, this was it: https://mightyapp.webflow.io/