Reading through the thread, it might help to mention text-based* applications exist.
These could be an ideal match for slowly updated e-ink screens.
Examples are the
https://newsboat.org/ RSS reader and Mutt mailclient
https://en.wikipedia.org/wiki/Mutt_(email_client)
I'm not affiliated with either BTW.
These programs tend to be simple, lack images and are entirely keyboard driven (no mouse cursor).
Screen updates usually only occur after you issue a keyboard command.
They do sacrifice features and convenience, and the learning curve can be steep. And it'll likely require using another system than Windows. It all depends on how 'tech-savvy' you are (or get a helping hand).
*or CLI/terminal/shell programs. Basically <90's tech, which forms the basis of unix-like systems and windows.