You need to be unplugged for 12 consecutive months for Proton to delete your account because of inactivity though, which seems fair for free tier accounts. A simple login is enough to prevent this, you do not need to send an email or whatever, simply log in once a year. You also get reminders sent to your recovery email before this happens. Data storage for inactive free tier accounts isn't free for Proton.

I believe you're right. However, if memory serves, the ads did change occasionally, meaning the screen had to refresh, leading to increased battery usage.

I just sent them a message asking them to disable the ads on the kindle I had recently purchased, and they did so for free, no root needed. That was a few years ago though, so I doubt they do that anymore...

I find that Neo covers most of my needs. Although there is one thing in particular that I miss: swiping actions on seperate icons to launch another app/action. I haven't used Nova in a while, but it had nicer previews inside the options, and I find that Neo has a few minor bugs that annoy me at times. But Neo has the things that are most important to me: multiple pages, tabs or folders in the app drawer, icon pack support, search and gestures (not on each icon, as noted earlier). I also miss the ability to place icons between the defined grid as in Nova.

I use KOReader both on Linux and Android, and I love it! I used Calibre's own reader for epub files earlier, but have since used a bit of time getting to know KOReader and its features better, and it suits my needs very well.

I stopped using Nova Launcher when it was aquired by an analytics company, since launchers usually have access to a lot of permissions, and I don't trust a company dealing in analytics to operate in good faith with that access. I have used Lawnchair 2 and recently switched over to Neo Launcher.