Okay, I just noticed that you can pass structs to functions by ref, as well as other types, but can’t set function output by ref, as well as other types. So it’s not strictly a struct problem(Of course it is not the case for actors which passed by ref by default)
I have same situation as you and I store only index of a struct I want to modify later and above mentioned Set Members in function to modify it by ref.
Edit for example:
Yeah, you can just store index of struct in array to avoid constant looping through the array to find the one you want