An enumeration is a fixed list of options that you can't filter based on conditions or anything else for that matter.
I think you should setup an entity holding the values you currently have in your enumeration and associate this entity with the entity that currently holds the enumeration. Then you can filter data based on conditions or xpath to show only those options you need according to the conditions.
You can not change the values of an enumeration during runtime, but maybe that's not what you want to do.
Do you want to preselect something based on a condition? If yes, you should call your page via a Microflow. Within this microflow you can preset the enumeration based on your logic.