K-Money

I think BookLore ticks all your boxes. It has opds as well as kobo syncing. You can also read via the built-in reader on the web to keep things synced. It supports separate libraries so you can keep your textbooks and research papers separate.

It’s being pretty actively developed with new features every few weeks. I’ve been very pleased with it after trying half a dozen other alternatives that were never quite smooth enough.

Haven’t tried it with graphic novels but BookLore is being very actively developed so if it doesn’t already support them it may be a worthy feature request.

Sounds like DumbAssets might work for you.

That’s not too far off what you can do here. https://www.nationstates.net/

There are several decent note apps that strive to replace Google Keep, but they all seem to fall short on the one feature that keeps me on Keep: Reminders. Being able to jot a note and have it pop up later today, on the weekend, or on an arbitrary recurring schedule is the primary use-case for me. Joplin’s come the closest but the reminders were unreliable, and an unreliable reminder is a useless reminder.

There’s also something to be said for the number of clicks/menus/presses it takes to create a note. If it’s meant to be just a quick note when something pops into your head then it’s nice if it doesn’t take more than a click or two to get it down.

One last thing. A feature that I think would greatly enhance adoption would be an option to import existing Keep notes from a Google Takeout into your Simple Notes.

Thank you for that link. I found that page to be quite enlightening.