More to the point curved end bracelets, I have just realised watch bracelet manufacturers who sell curved end bracelets do it wrong. I could own a 36mm watch and you may own a 50mm watch. Though both are circular and wear a 20mm strap. The curved end might not fit.
A possible solid would be the watch company’s include/offer curved end links for their products.
It’s because it’s not standardized and every watchmaker differentiate the case one another. Hence, it’s better to get one from the manufacturer or 3D print it by yourself.