Hey Geeky,
You can use a UI policy or Client script to hide the variable, and make sure the Run scripts in UI type field is set to Mobile/Service Portal. In that case it will only run on service portal and not in the standard catalog view.
It's the most simple way to achieve the solution you want. If my answer helps then please mark it Correct and Helpful.
Thanks and Regards:
Utpal Dutta
