This won’t help you with your syncing challenges, but just FYI, you don’t need to install the Dropbox app on iPhones or iPads to sync Scrivener to Dropbox–iOS Scrivener itself takes care of linking and syncing. This means that iPhones and iPads don’t count toward the 3 device Dropbox limit, unless you want to install the Dropbox app on those devices for some other reason. But you don’t need the iOS Dropbox app to sync iOS Scrivener via Dropbox.
(You do need to install the Dropbox app on Windows and Mac desktops if you want to sync desktop Scrivener using Dropbox, and those installations will count against the 3 device limit.)
Late last year I went through the same thing, when I returned to a novel I’d originally worked on over 2021-2022. So I know exactly what you mean about being overwhelmed! However, I committed myself to doing Novel November (a NaNoWriMo replacement) and used that as a way to reengage with the story. Spending a few weeks reviewing the outline and all of my notes definitely helped, but it wasn’t until I sat down and started writing scenes that I really began to remember who the characters were, what they wanted, and what they were willing to do to get it–that’s when things really began to click for me. I’m at about the halfway point of the book now, and feel confident that I’ll be able to complete the first draft within the next 4-6 months.
All that to say, I wish you the very best as you get back into to your story. I encourage you to take your time and extend yourself a ton of grace as you refamiliarize yourself with this world you’ve created. Most importantly, have fun!
Best,
Jim