One thing to say about Boox and other Android eink tablets/notes, is that they only have battery life comparable to a traditional LCD screen tablet.
I did a good amount of investigation on eink devices late last year and early this year, as I wanted something I could write notes on, with an eink screen and the battery life benefits as well as being supremely readable in sunlight. Many of the big sellers run Android or a forked version of it, with optimizations for eink, but there’s only so much that can be done with Android and eink, it seems.
But some other devices run a Linux-based OS, which is the case with Remarkable and some few others with leading battery life and screen/writing feel and responsiveness.
You can use the Remarkable without a subscription, as others have said. I didn’t get one solely because the Remarkable Paper Pro was just too huge for what I wanted - a paper notebook replacement with digital capabilities and a non-emissive screen.
If I had known this was coming I would have held off! At least to try it out. As it stands, I bought a newer company’s device, which is decent, but runs Android, so there battery life does suffer. Though I can get around 25 hours out of it.