Login to the OneNote Windows OneNote app with both your Uni Account and Personal accounts
In your Uni Account , open the Notebook with the Sections you want to transfer to your Personal account
Now right click a Sections and then choose the “Move/Copy” option. Choose as the destination location an existing Notebook (or create a new one beforehand in your Personal account). It may takes some time for OneNote to sync over the Internet
Repeat step 3 until all sections have been moved to the Notebook in your Personal account