I wish there was a universal standard for highlights and annotations. Probably the closest we have now is syncing all that through calibre. I personally use the kindle app on an ipad, sometimes casting to my tv so I can lay in bed and read comfortably. I've tried so many epub readers and unfortunately kindle is the only one I like, that's still maintained. Marvin3 was the best but it's unmaintained and the annotation menu is broken. the kindle export is pretty shitty. It''s not super useful when you have no context as to what you're highlighting, and I think they make it shitty on purpose so you have to stay in their eco system.