Add Donate next to Add to Cart button on Product pages

Site URL: https://www.bommestudio.com/shop/protective-face-mask-reusable-fabric

I am offering a product that is available for purchase and to donate. I have both buttons set up on the product page but I'd like to add the donation button directly next to the add to cart button (labeled Pre-Order).  Is it possible to do this with custom css?

Trying to achieve the same thing, or adding a donation section to the checkout would be good. Is there a way to connect the cart and the donation block?

I am also looking to do the same, we want people to book onto workshops through the site but on a Pay As You Feel basis. It would be good if people could select the amount they pay for a product or be able to add a donation onto each purchase. Is there anything in terms of custom code that could do this?