as far as i can tell, the best most of us can do is to navigate through older observations one page at a time. so that’s not a great solution if you have a lot of observations. (it might be possible for someone to write a browser extension that will let you go back to a specific page though. not a great solution either, but better than going one page at a time.)
i think this is already covered in the first part of this request: https://forum.inaturalist.org/t/better-integration-of-observations-and-journal-posts/1267.