Do VAT or duties surprises kill conversion at checkout?

I'm running an e-commerce store and constantly struggle with cart abandonment. I've noticed that many customers seem to get frustrated when they reach the checkout and suddenly see unexpected VAT or duty charges added to their total. These surprise fees appear to be a major conversion killer, causing potential buyers to exit the purchase process entirely. I want to understand how these additional costs impact customer behavior and what strategies I can implement to minimize their negative effect on my sales funnel.