It looks like a negative Covid test is required one day before flying from Croatia to the U.S. Does this still apply, and where in Dubrovnik is the cheapest/best place to get the test and results within 24 hours?
Consult your hotel would be my first step. All airports in major tourists dependent cities with pharmacies like Dubrovnik have covid test.
Yes, it still applies. Another alternative to a pharmacy is a proctored test, such as this https://store.optum.com/shop/products/abbott-binaxNOW-COVID-19-ag-emed-at-home-test-kit-2-pack/