To what extent are customers put off by checkout in a foreign currency?

Shopify Payments is currently unavailable in my country (Poland) which means I am not able to provide checkout in currencies other than my store’s main currency (USD). I have read lots of other threads on this topic and there doesn’t seem to be any solution to this apart from waiting and hoping for Shopify Payments to be made available in Poland. My question is how much are customers put off by checking out in a foreign currency?

I have an app installed to display the customer’s local currency but at checkout it reverts to USD. I have recently started advertising in countries other than the US and the adds to cart and checkouts initiated are looking quite promising but I have not had any purchases yet. I’m wondering if they are put off by suddenly seeing USD or if there is something else that may be wrong that I need to address.

I’d be grateful if anyone can share their experiences on this.