What’s the difference between a connected app developer and a connected app

Connected app developer: It is a Salesforce developer or ISV who builds API integrations or external apps that can access Salesforce data as a connected app. As a developer, you can build a connected app for your org, but other Salesforce orgs can install and use it too.
connected app admin: you install, uninstall, and when necessary block connected apps from the Salesforce org. You also configure permissions and policies for the apps, explicitly defining who can use the connected apps and where they can access the apps from. These permissions and policies, which include profiles, permission sets, IP range restrictions, and two-factor authentication, provide extra security for your org.