Itch is not designed in such a way, so they did not provide the usual tools. There is a feedback button that has a suggest feature option to give this kind of suggestion directly to Itch.
Breaking it down by year has the benefit of making the big task smaller. If you do not want to break it down into smaller tasks, there are not that many things you can do to still tackle that task. Especially if you use a high fluctuation sorting like Popular or even New & Popular. Popular also has a new-ness factor that contributes to apparant popularity, but less so as compared to new&popular.
Going backwards through recent for your selected tags in paginated view and keeping a bookmark at your last visited page should catch all or most of the games. You need to use /oldest/ in the url instead of /newest/. I do not know if there is a button for that. https://itch.io/post/2493289