That’s correct—in order to edit/manage an app under your account, you will need to be the user who created the app. If you wish for someone else to be able to manage/edit the app, you will need to transfer the app to them entirely. This can be done from the Admin section of the Apps on Account (Created Apps) page:
If someone leaves the account that created the app, they should transfer beforehand using the method above. For other scenarios, you can reach out to developersupport@zoom.us for assistance transferring the app.