The line item properties (custom product options) data is store in the field line_items.custom_attributes of the Shopify Abandoned Checkout data.

Selecting this field in the app will export all line item properties per line item in JSON format.

To only extract specific line item properties and place them in separate columns, you can use a formula like this under the Calculated Fields section:

search_attributes({{ line_items.custom_attributes }}, "Birthday", search_key="key")

You can basically just copy/paste this formula and just replace "Birthday" with the name of the property you want to pull.

Here's a screenshot of what this looks like in the app:

And here's where you can find the property names in the Shopify Admin:

Sample output when exported: