How many pages are there in your project? Makes a difference if there are 2 pages vs. 200.
I would suggest making a copy of your project file. Then do the following, but ONLY to the copied version:
- right-click (control-click) on the project file in the Finder
- select Show Package Contents
- I’d view in List mode, order by size
- my biggest sub-area is Pages. Most likely yours will be also. The combined size of all my non-Pages stuff is less than 2 Mb. So if yours is a lot larger it may be worth investigating.
- open whatever seems to be your largest subfolder. There may be Child Pages inside the subfolder.
- my biggest Child Page or singleton page is less than 700k. That number is not so important in and of itself. But if you are seeing a page that’s 2 Mb or 10 Mb or similar then it seems you have some “stuff” that has not been warehoused.
From your description it seems you have only partially warehoused. That’s fine. But then navigate to those pages in your Finder where those pages are located and see if there’s something still there.
Sometimes folks add something super big that they forget about. E.g. a self-hosted video which is no longer used but still remains in their project file.
In the end it takes a bit of investigation. So be patient. But it does sound like something is off.