Your whole book in one spreadsheet — clients, policies, journal, reminders, proposals and your product catalogue. Keep it somewhere you control. It is yours whether or not you keep using AdviserOS.
One workbook, one sheet per kind of record, with a Read me sheet explaining what is in it. It covers everything filed under your own name. A client that another consultant shared with you belongs to their book, so it is in their backup and not in yours.
Upload a workbook you downloaded here. Nothing is written until you have seen exactly what would happen and pressed the second button.