Welcome to Community @info932,
We have a limitation in converting data files from QuickBooks Online to QuickBooks Desktop. Here are the things you need to check before you convert.
Some of the features in QuickBooks Desktop is not available in QuickBooks Online. If there is a missing transaction, you can manually enter it in QuickBooks Online as a workaround.
Check out this article link for additional questions about converting data files from QuickBooks Desktop to QuickBooks Online: The QuickBooks Guide to Converting QuickBooks Desktop to QuickBooks Online.
You can visit this QuickBooks Help article to learn more about QuickBooks.
Just drop a message in the comment section if you have follow-up questions. Have a great day!