This is a big question and there is no quick / simple answer here
1) Project Settings are all stored in your Project Templates - you will need to have those (look in Support / Options / Project Management and Support / Options / File Locations - those will tell you where your Templates and Custom parts are stored on your PC including
- Project Folders
- Project Templates
- Block Definitions
- Custom Export Format Definitions
- Office Synchronizer Location
- Project Library for Earthworks System
2) Your Options file can be saved out from Support / Options and stored locally on your PC - you will need to do that each time you update Options and have that location sync across to One Drive
3) Custom Setups like Drafting Templates - Sheet Layout / Drafting Templates (you can find the path to that from here)
4) If you have Custom Feature Code Libraries, Material and Site Improvement Libraries etc. you will need to know where you store those and sync them. They can be anywhere on your PC (I have one Custom Setups Folder on my Documents folder where I keep all these things
5) Custom Menus and Toolbars - if you export these - again these can be anywhere on your PC you will need to sync those
6) If you save out Layer / Layer Groups then again those can be anywhere on your PC
7) If you save custom Road Templates or Sideslope Templates then again these can also be anywhere on your PC
8) If you use some of the drafting functions, things like Label Styles and Table Styles etc can all be written out to anywhere on your PC
9) Your Menu Layouts etc are stored separately and are unique to each installation and are created when you load a custom menu etc. so no need to track those down.
Be aware that running Sync on things like your Project Folders while in use has been reported to create issues with some types of data e.g. Images, Point Clouds, Photogrammetry data - if the files get Syncd while in use - so be careful using this to share all your Projects and have them continually synching in background.
I think that this covers the majority of the things that you need to think about at least.
Alan