Disable ZTP:

set system ztp disable

It's possible to use data ports for management. It's done via Interface Management Profile:

• Create in Network | Network Profiles | Interface Management Profile
• Then attach to Network | Interfaces on the Advanced

CLI verison:

set network profiles interface-management-profile mgmt https yes ssh yes permitted-ip 10.15.15.37
set network profiles interface-management-profile mgmt permitted-ip 192.168.0.5

Service Route Configuration

If the management interface does not have access to the internet, this can create interesting challenges as it will not be able to retrieve updates or perform cloud lookups. A workaround is to enable service routes that route specific applications, services, or protocols via the backplane onto a designated data plane interface

• Device | Setup | Services
• Service Route Configuration