Javascript issue with upsell button on order form

I have some custom javascript functions running great on an order form (inside a jQuery(document).ready… block) but I’ve recently added an upsell button to the form. Clicking the button adds the product as expected but also seems to reset everything my javascript did when the page was loaded.

The closest similar question I could find was https://integration.keap.com/t/order-form-javascript/12277, which lead me to look into using the ajaxComplete event. That might work, but that event fires 10 times on my form each time I click the upsell button, so I really have to wait for all 10 events to complete before I can start changing things around on the page, right? Is there a better way to do this that I’m overlooking? Thanks!