As much as I love the hacker spirit of cracking open hardware and software and bending it to your will (whether or not it was designed towards that end), I enjoy my reMarkable precisely because I can get away from the ubiquity of computing and needing to constantly tinker with and repair software.
I've fucked with Gentoo and Arch for so long that sometimes I just want a break from it all. No dependency hell, no bugs, esoteric stack traces, nor popups, advertisements, notifications, nor distractions. Just some pen and paper, except without the eraser shavings or ink blots. Not having to scan your notes to digitize them is a nice bonus as well.
Especially since the pandemic and in the WFH era it's nice to get away from the omnipresent touchscreen or mouse and keyboard interfaces and deal with something a little more tactile; something reminiscent of a less perpetually online era. I'm tired of being hyperconnected to everything. Not to mention all the problems from staring at LED monitors all day long.
Sometimes I don't want to troubleshoot software; I've done enough of that already.
Personally I completely agree with you, and could have written almost exactly that paragraph - I too have a ReMarkable (the 2nd / current version), and love using it as it ships for both note taking and especially for reading ebooks/PDFs ("especially" just because it's what I use it for more, not because that's what it's better at - in fact, its UI for reading documents is among its weaker points and I hope they improve it in future software updates).
However it is worth pointing out that you can SSH into it, and there are a fair few 3rd party tools and hacks for it - so far I've avoided trying any of them as there's nothing that I want strongly enough to have even a 1% risk of bricking it to worry about. But I'm tempted to start playing around with it someday.
This is the best list of stuff for the ReMarkable that I'm aware of, though I don't know how complete it is / how many released tools or guides there might be that aren't included here: