There are quite a few. In order of preference, I used/tried:

• XMPP (Android-Conversations; Windows-Gajim)
• Element/Matrix
• Session
• Discord
• Slack
• Twinme
• Teams
• Skype
• Facebook Messenger
• Instagram DMs

I was using landrop before. Works fine but the GUI was just a bit off, not intuitive enough. That’s Localsend’s biggest improvement IMO.

TheOnion worthy title.

In hindsight, that’s what I’d go for. You could have audiobookshelf, tachiyomi or any of your favorite android reading apps. But the Kindle does what it does well, and for relatively cheap. Maybe in 5 years I’ll reconsider, if my kindle ever dies!