Good news for you! The ReMarkable is build on Linux and you can direct access to the whole system via SSH!! They even give you the su password so you can do _anything_ you want with it!

You can break the custom integrations that they created or even brick the whole device.

But nothing is stopping you from logging into the system and modifying anything you want. There's actually a whole ecosystem of 3rd party mods and software for the ReMarkable!