Hi Heddy, great answer. Thank you so much. you basically gave me all possible solutions. This is by far than what I got anywhere else.
Yeah, I think I will choose the option 3 as our insurance is for whole order, no need to split it or attach to product level (if it needs to, then option 1 will be the best).
Someone also mentioned to use cart transform api to do it: https://shopify.dev/docs/api/functions/reference/cart-transform, which is similar as your option 1.
Thank you so much Heddy.
Regards,
Dean