o I have to use the 10DLC if I have the shortcode.
10DLC and shortcodes can coexist, 10DLC is not intended to replace or supersede shortcodes. Instead, 10DLC aims to improve existing long-code messaging programs, expand customer communication strategies, and provide more opportunities to deliver a better mobile experience. Existing shortcodes remain unchanged and no action is required. Dedicated shortcodes are still suitable for use cases that require optimal delivery, reliability, and traffic. Short codes are expensive and not always an option in every business area, by contrast, 10DLC is an affordable option for some use cases.