You can do it either way depending on how you want to handle things. Keep in mind that some uploads can be marked as demos, so you can easily have them on the same page as the main game even if the latter is paid.
A question on demos and game pages. When a page is first posted Itch gives the page a boost. When a game gets upgraded from demo to released does it get another boost? if not then it would be better to delete the game profile and remake it as you would get another boost?
No, it would be better to post a devlog marked as Major Update or Launch. That way you'll have both the continuity, and the benefit of jumping forward in the list again.
