Thanks, but I don't use e-readers as they are not available here.

I've been using MoonReader for many years now and settled on pretty good parameters that make the reading experience very comfortable on both my phone and my tablet.

Calibre? https://calibre-ebook.com/

I don't understand what this is doing. Can't you sideload any ebook onto a kobo anyway? Never had an issue on my Clara

On my Kindle I use KOReader Zlibrary plugin which allows you to download books from within the reader. It's more convenient then any send-to-kindle workflow.

https://github.com/ZlibraryKO/zlibrary.koplugin

This is a genius way to farm ebooks while providing a useful service. I personally just use Google drive though.

Or... just a USB cable?

Handy, but a book lover with an ereader probably already uses Calibre :)

I don't recall ever needing anything special on my Aura H2O. It's one of the reasons I chose Kobo in the first place. Just copy any file onto it.

If you mean stripping drm I used Calibre for that but mostly I just avoid buying books with drm where possible.