Dear Lissa,
Greetings! Thank you for posting in Microsoft Community. We are happy to help you.
Per your description, you want to export the personal notebooks into the individual notebooks on SharePoint.
I'd like to help you, we can work together to narrow down and resolve the situation.
Per my experience, you may use OneNote application to move the personal notebooks to your SharePoint site.
As you have exported the personal notebook as a .onepkg file, you may try following steps to move it to SharePoint site:
1. Open OneNote application (Note: it's not OneNote for Windows 10).
If you don't have it, you can install it by using this package: Download OneNote.
2. Sign in your Microsoft 365 work or school account in OneNote.
3. I suppose the .onepkg file is stored on your computer.
Go to File > Open > Select This PC under other locations > navigate to the location where the .onepkg fil is stored.
Note: If you don't find the file, select OneNote Single File Package or All files to display the notebook package (as shown below)> click Open >on the pop-up window, click Create
4. After your personal notebook opens, go to File > Share > Select and click your SharePoint location, click Browse > on the pop-up window, firstly put your SharePoint site URL in the path location, as shown below, press Enter key, then choose a document library to store notebooks, give your notebook a name and click Open, then Move.
5. You may see a message saying Your notebook is now syncing to the new location.
Then you can go to your SharePoint site in browser and see if you can see the notebook showing in Documents library.
Do let me know if you have any concerns or if my understanding of the scenario is not consistent with yours, please feel free to point it out. I will do my best to help you further.
Thanks for your time and cooperation! Hope you have a nice day, stay safe and healthy.
Sincerely,
Tina | Microsoft Community Moderator