I used to copy/paste shipping in PayPal and import it into a spreadsheet
but it was a major hastle, but now eBay's gotten rid of PayPal. This
seems like one of the most basic / essential options for any seller. The
year is 2021.
I figured it out! Seller Hub > hover over Payments > Reports >
Statements > scroll down to Shipping Labels > BOOM! Fortunately it
automatically shows previous months' total which is what I was looking
for.