I feel you. I have a writing partner, and me and him have this Google doc where we write down ideas for future stories when we come up with them.
It's usually a summary consisting of 1-2 sentences about what the idea was.
So this is about how it's formatted.
Idea 1
Idea 2
Idea 3
etc.
The reason I tell you this, is because the doc is also almost 5 pages long.
5 pages of vague ideas is still good, any sort of place to organize your own ideas is good. Every small stone you put at a time is eventually gonna turn it all into a mountain, so keep building off those until you can stitch them together.
I basically focus a lot on building up that one "big project idea" that I'm sure many have though it mostly goes in my head.
For now, I have a basic list of my character names separated into what allegiance they belong to(main cast, supporting cast, minor characters, antagonist group A, antagonist group B, etc) though I'm hoping to expand it onto small biographies and defining characteristics so I can have a clearer picture of all of them.
I also have an outdated basic plot structure(basically each arc and what happens in them in broad terms) that I should probably update someday.