Let me just say that the Remarkable also runs linux.
Not only that, but I've been blown away by the ongoing results from the team at Remarkable. I only have the Remarkable 1 but they continue to ship updates for it, and these updates are often really substantive with sometimes profound new features. Their cloud service is free, no aggravating subscription stuff and even though they have the remarkable 2 now, they continue to kill it with the updates to improve my experience with the remarkable 1. They, as of right now, have my undying loyalty and appear to be a truly customer focused company. I'd love to buy their entire team a couple beers.
Don't get me wrong, I love pine64 too, but they're way more oriented to us hacker types than ordinary people and I don't want to have to hack together a functioning device with everything I own, though I think they're doong good work none-the-less.
There is also an opkg-based package manager and repo with many packages: https://toltec-dev.org/