Migrate to Calibre and use Calibre Virtual Libraries. However based on the comments I’m reading, it looks like you want something that is not application based. Good luck with that.

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Oh yes that’s much needed, thank you.

Who in FOSS hurt you?

Not sure whether this would meet you or anyone competent’s criteria for “good”, but here is mine:

• Syncthing my Calibre Library folder on my primary PC
• Mobius Sync to my iPhone
• Load books (saved in main folder by author name sortable by date modified) or news (they’re saved in “calibre” folder by publication name) to iOS Books app or PDF in native Files app

That way I load whatever I am currently reading.

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Oh yeah, and Kovid posts a tracker for most used news sources so you can see what works and what other people are enjoying. https://calibre-ebook.com/dynamic/recipe-usage

Also, if you like to view by covers, here is what it looks like in Cover Grid Layout!