I would much rather have a A6 or A5 sized display or any other standard size for paper notebooks.
The trick to something narrower is to get comfortable with doodling in landscape mode, e. g. for classroom notes, and scroll (and orientation-switch) accordingly when neccessary. Ideally you'd have physical complementary buttons present, but a good touchscreen with palm rejection works as well. To-do lists and the like can be done vertical mode. In other words, a digital notepad.
Now you only have to built a corresponding smartphone-sized, pen-focused, modular and connectable open-standards general-purpose computer. :) ... :(
The reMarkable looks too underpowered and maybe too enshittified (subscriptions, lock-ins) to be used for anything else but a digital notepad.
I will say that my supernote really is just a digital notepad. I keep all my work to do lists organized on it. But since it's Android and supports side loading apps, I have the Kobo app and read a ton on it even without a backlight.
I don't see how that can't be improved.
This smells more of a fundamental problem to me where vendors enshittify their devices to try wooing complete non-users, e. g. people who are too incompetent to work their head around using a penabled smartphone-sized machine and its notetaking/sketching applications exactly like they would use an analog pendant (the classic pocket notepad/pencil combo), or people who bore others with tedious litanies about how "the screen is too small". The latter crowd is well-cared for options-wise, so this is virtually a non-problem. I want to carry around and use a digital pocket notepad on steroids, and not a bloody whiteboard.
> I will say that my supernote really is just a digital notepad.
I only tested the Nomad's pen functionality (as well as ergonomics resulting from its size) and was very pleased. It's weaknesses lie elsewhere.
Remarkable has the roughly A6-sized Paper Pro, Kobo has three e-ink devices with styli and good screen ratios, and Supernote has models named A5 (and A5 x2) and A6 after the paper sizes. I think the options are quite good.