I got a Boox e-reader with a 7.8" hiDPI screen earlier this year (my old Kindle was 6"), and let me tell you, it's been transformative. My biggest nitpick with the old kindle was the screen: it was a little smaller than the average paperback book page, which meant that I was constantly turning pages to read anything of significant length. With a 7.8" screen, ebook pages are almost precisely the same size as pages in a traditional hardcover book. So if you're used to that kind of reading experience, it's an easy transition. Oh, and the screen is also big enough and high-res enough to display tables and images at full size, without awkward multi-line clipping. So you can actually experience books as they were meant, instead of dealing with issues in anything that isn't just a stream of text.
I've also really enjoyed using Android (albeit in a modified form) so I can use torrent clients, FireFox, an email client, an Airdrop knockoff, and an RSS feed reader to get content onto my device. You'd think it would be distracting to have all of that at your fingertips, but the limitations of e-ink really rein in the desire to mindlessly browse HN and reddit.
And the WACOM layer that's integrated into the display is truly awesome to use for notetaking, drawing, and even keeping score when I play card games. I've basically moved all of my notetaking over to my ereader. And I don't even have to charge the pen.
One big issue, though? There are a million cases out there for Kobo and Kindle devices, but nobody makes them for Boox devices besides... Boox. But if you're willing to DIY a bit, it turns out that the Nova 3 is almost the same dimensions as the iPad Mini 4/5... so just buy a case for that, and if it's a snug-fitting case, make a couple of cuts in the case to let it stretch over the ereader, cut out a hole for the power button, and you're golden.
Disclaimer, though: Onyx/Boox, the Chinese company that makes my Nova 3 device, is in flagrant violation of GPL with their Android modifications for their ereaders. So you should be aware of that before you decide to buy one -- if you're cognizant of that kind of thing, I assume you don't want to give them money. I figured that it's at least better than giving money to Jeff Bezos and locking myself into another walled garden (that can't even read epub files!). YMMV.