Step 1 - Remove issue linking permission on your project
The first thing you need to do it to restrict who can create links in your Jira project.
You do not actually want issue linking to be available on your project, except through Elements Copy & Sync Data Panels.
1 - Go to Project settings > Permissions :
2 - Click on Actions > Edit permissions :
3 - Restrict the "Link Issues" permission to the project Role "Administrators" :
Of course, you may want to allow some other users to link issues within your project. Feel free to configure your permissions as needed: issue linking will only be restricted to Data Panels for users who do not have the native Jira linking permission.
That's it! Your project permissions have been updated as needed.