I don't like .epub. I understand the reasons why this format exists, and I am 100% behind those reasons. But it's because I don't find any EPUB readers appealing to me. Just give me a FoxIt Reader clone for .epub, that's all. But naaaah!!, every single fucking e-pub reader that I tried must be a fucking library collector instead, like it's 2000's Windows Media Player style. I hate that.

As such, whenever I get my hands on an .epub file, I go to an online converter, convert it to a .pdf file and nuke it from my system. Then the .pdf gets opened in my FoxIt.

Have you tried foliate? Their embedded reader works quite well for me.

As someone who loves FoxIt reader, I'm building https://merrilin.ai to be the best damned ebook reader out there, to support PDF and epub. FoxIt's annotation system is one of the best I've experienced and I want to design one that is just as good if not better.

Hmm, Sumatra PDF perhaps?