Asking users feedback after the checkout drop

I'm working on the e-commerce checkout experience and the GA shows we have quite a big drop-off rate.

I assume, the users often don't finish the checkout process, but just add the items to the cart and then observe the full order price.

I know the 4 most popular reasons for the calls from the user support. Our CEO wants (of course) to reduce the drop-rate and suggests to use the user feedback popup when the user leaves the page. I see this as a dark pattern that makes our website perceived as needy and distractful.

The option that I usually see is showing this popup when cursor is moving up the page, towards the tabs. NNg say it could be not attempt to leave, but just the intention to switch to a different tab and then probably return.

Another option I thought of is to add the pretty subtle "back" button and ask the user about the leaving reason after they return to the previous page.

What do you think? Shall I use one of two options mentioned, or something else?