

If you want simplicity I recommend skipping all self hosted solutions. You can set mihon to download X chapters ahead for offline reading and delete chapters as you read. On a kindle I’d recommend save as archive and/or cut tall images (webtoons).
Ebooks take no space.
Stick to calibre on your computer and transfer via netshare using a file browser (android: solid explorer) to copy stuff over. That’s what I do.
Why is that thing scary?