there is no BigFix Relevance language inspector that evaluates powershell, but it would be helpful if it existed (but not sure it is possible). Here is an enhancement request for it https://bigfix-ideas.hcltechsw.com/ideas/BFP-I-76 if you want to vote for it.
Your question about setting text based on a value, before you re-edited the post, this is one approach that may make the code easier. You can create a string that contains the possible values and the text that those values represent then parse the text. Something like
Q: preceding text of first ":" of following text of first ((concatenation "" of unique values of string value of selects "HealthState from DCIM_Battery" of wmi "root\dcim\sysman") & ";") of ("1;Something1:2;Something2:3;Something3:4;Something4;5;Something5:6;Something6)")
A: Something5
T: 93.265 ms
I: singular substring