Yup. And you can implement something that loads all the content up until that point when the user presses F5 in the middle of the page. And you can implement smooth scrolling that takes into account your sticky header. And you can make your pagination based on the ID of the last seen page item instead of based on count.

The question is, is this the best use of your time? Are you willing to invest more time in it when you give it to the user? Because the user will do something you haven't thought of, they will break it, and you will need to fix it.

You can, but that means if a user scrolls through a page and decides to share it by copying the URL they'll get a link to the page they've just scrolled in to rather than the one they've just read which is very likely to be wrong. It's something that makes me much less likely to share links.