Emulate / Custom buy now button on checkout button click

Hello guys,
A brief on my situation - We plan to have 3 subscriptions displayed in a Pricing Table Format, the customer can select anyone of those and then move to fill a questionnaire after filling the questionnaire they reach a page which leads them to click on the checkout button to make the payments - we need this checkout button to act like the buy button because it needs to clear all the previous items in the cart - is this possible?? also alternatively is there a way to empty the cart via code?

Here is my site Read-Only: Webflow - DAM Health