I see reMarkable says[1] you can use it without a subscription, but I'm not confident they won't pull the rug under my feet.
[1] https://support.remarkable.com/s/article/Using-reMarkable-wi...
That being said, my girlfriend loves her Supernote too, so there's plenty of alternatives.
I'm a sucker for high-quality materials and thoughtful aesthetics. Metal / glass over tacky plastic.
Being an "excellent offline device" also matches one of my core requirements.