I'm not sure about the "audiobooks" part but you can use your browser from android to connect to calibre https://manual.calibre-ebook.com/faq.html#over-the-air

BTW I used for many years Moon+ Reader to read aloud my ebook on android. Not quite as a real audiobook but good enough https://play.google.com/store/apps/details?id=com.flyersoft.moonreader

Weird in what way?

I'm an avid Obsidian user but I didn't know about Matcha. It's really cool

https://smarthomescene.com/reviews/aqara-fp2-human-presence-sensor-review/

UPDATE 24.04.2023: Aqara has released a new firmware update 1.1.6_0005.0025 which enables local control. The FP2 can now be used without an internet connection, hub, or app dependence in Home Assistant after it’s initial setup.

So, yes, after the initial setup (you may need an internet connection to download and install the newer firmware) no internet connection is needed at all.

I prefer to use services as keepa or camelcamelcamel to track price drop (besides prima days & co)

Are you sure about Paaster supporting Markdonw? I only see syntax highlighting https://paaster.io/GtlseaIIhqtfcsZV1C8sS#BgT9miwSaeKzMLQ-Ch6d3KZlgfCmIR32dpYr06HXYTw