[Quoth]

I've Aldiko (OK for ePubs) and Bluefire (sort of does PDFS and ePubs).
The problem is that it's awkward to import ebooks from Calibre via USB. It's even more awkward to update ebooks I write and edit (via LibreOffice Writer -> Calibre).

I'd have my SD card as external storage, but some older apps don't work at all with external SD card even for data. So I've reformatted the SD Card as "expanding" internal storage.
I have a 6" Android phone, 7" Android tablet as well as a variety of eReaders.

So what epub app for Android (free as I have no payment method for Google Playstore and without adverts) works with Calibre to be able to install / remove ebooks without using evil menus on the app?

I don't usually have my phone online (and never other than WiFi), so the adverts in Aldiko or Bluefire (or both?) are rare.

I'd like annotation. That seems to be a premium feature on Aldiko. However simply working like Kindle/Kobo/Sony/Nook with Calibre without annotation would be fine.
I'm not interested in connecting to servers etc, only USB just the way I use the Kindle/Kobo/Sony/Nook eink ereaders.

I removed the Amazon Kindle App as it's trying to "connect home" even when it's not explicitly opened and with Mobiile data disabled. Which results in pop-up error messages.

Both Adobe Editions DRM and Amazon Kindle app seem to be "spyware". I've no wish to report what page I'm on or book is in use.