Is there a way to add a login item in the terminal without triggering a permission dialog on macOS 10.14 and above?
I don't have a lot of experience administering/doing mass deployment of scripts over Jamf but I am positive the following links would be very helpful for you. I believe what you are looking for is how to work around Apple's Preferences Policy Control Payloads (PPPC).
Please take a look at the following resources:
GitHub - homebysix
Apple Official Doc about PPPC
GitHub - Jamf
Basically, you want to figure out what you want to explicitly whitelist and preauthorize these using the MDM profile utility and deploy the profile you created along with the payload.