Lock/Freeze an issue/epic using conditions or property keys

[Jon]

im using jira cloud and our project consists of epics with issues. as they go through the workflow there are stages where we want to add protection measures so that other users don't mistakenly edit the wrong field. all users have certain fields they have to edit through the workflow but there are some fields that are conditional on others and others that we would want to freeze after another user fills in their field. 

specifically I was looking at conditions but I cant find anything that would work nicely since the things I am trying to do are when the issue/epic is in the particular status, not necessarily in a transition.. so was wondering about the property key and how that would work. the possible things I would try to set up are such as:

-if XXX custom field is filled in lock YY field.

-if issue in XXX status then lock YYY custom field

-if parent epic of the issue in XXX status lock the field or lock the ability to change to another epic. 

THANKS!