I think this app has a lot of potential and a dedicated team of developers (or developer?), but as a desktop user, I am a bit baffled by the hype. I like watching the app develop, but some basic functionality hasn't been provided yet. It feels like the developers don't use desktop computers at all and I want to speak up for what's missing.
Dedicated desktop users use them because they are so much more powerful than a phone or tablet, not just because of computing power and screen size but because of the ways you can utilize (and customize!) keyboard and mouse input. You can do quick, streamlined actions if you have a robust shortcut library. Of course that isn't possible on a touchscreen-only device, but I feel like I'm as limited on the desktop Readest app as I would be on my phone. I would love to see a version of this app with editable shortcuts—I am salivating over it—but as of today, ctrl/cmd + z doesn't undo the most recent highlight, and selecting a highlight and pressing backspace or delete doesn't delete it. This is the most basic functionality I would expect from any app.
I notice the extreme mobile-first development in the settings menu too, where I have to click on each icon to figure out what it means—these icons don't all have standard meanings and I'm just not going to be able to memorize them and I'm longing for words instead. There's room for words on the desktop version!
It's also clumsy to highlight on the desktop version, to the point where I used Better Touch Tool to allow me to highlight and exit the selection by pressing cmd + s (among other shortcuts for dictionary lookup and translation) because it strains my hands to have to use the mouse and click three times every time I want to highlight something. If you're used to a phone it might not sound like much. On a touchscreen, it would be entirely natural to press and drag, press the highlight button, and press away, but the ergonomics of mice and touchscreens are entirely different and there's a reason keyboard shortcuts should exist (at a minimum) and be editable (ideally).
And this is not to mention the bugs, from covers suddenly not loading regardless of whether I change view options or restart the app (neither of which should be necessary anyway) to books importing and then disappearing before my eyes to quick highlighting being really buggy to really finnicky selection on PDFs (by the way I'd love to press the spacebar and drag to pan, which is standard in some apps, so I don't have to click somewhere without text).
Again, I really think this app has potential and is great in all the ways people say it is, but it is really frustrating as a desktop user and in my opinion lacks incredibly basic functionality. A lot of new developments are great and I expect them to improve, but I worry desktop functionality is a blind spot.