Honeymoon Recs – South of spain vs france vs italy?

Hi! My fiancé and I are looking to spend about two weeks along the mediterranean in the south of Spain, France, and/or Italy at the end of September/beginning of October of this year. We definitely like to relax, but would also like to be able to do some exploring and sightseeing, potentially some hiking. Especially looking for romantic vibes. We were going to do south of France and Amalfi, but heard Spain may be more what we're looking for. We've never been to any of them, so recs are appreciated! Looking to spend less than 20k preferably