I would do this with wp-cli. It’s a one line command:
$ wp post update $(wp post list --post_status=draft --post_type=page --format=ids) --post_status=publish
This command lists all pages that are draft (by id) and then updates all their statuses to “publish”.
This is of course if these are actually pages. If it’s posts, you just need to change page to post.
If you’re not comfortable with command line then you can bulk select all the pages within the admin backend and update their statuses there. (When you’re on the page list admin screen you may want to choose screen options in the top right and list more items per page so it takes you less time.)