Awesome.
So your struct should have a default damage type. That’s likely why it keeps feeding out another value. The logic for the struct is sound and a great idea. You just need something to build a cusomt struct from for your axe damage.
1 - Make your Axe Damage Type - I assume You’ve done this already, just for the sake of being complete.
2 - Make your struct - Which you’ve already done
3 - Make a data table and lay i tout to match your struct - Add a row for each type of damage - so a row for Axe, a row for hammer etc
4 - Before Apply damage, you need a Get Data table row.
5 - The row will return a struct, which you can break as normal, only now it’s filled with your data, not default values.
This way, you can store everything’s damage information and everything else per the struct you’ve made. How you choose to pull it out is up to you, but essentially, you just need to tell your BP which row to point to.
I used it to randomly generate weapon names stats and damage types on their spawn. When the player picked them up, it would feed this struct into a player weapons slot struct in the character/controller and I could send the dtata that way 
so that’s an alternative less headachey way to try
for the way you’re implementing though, you will just need to tell your BP - If I have an axe, pull out the row for Axe. I’m lazy, I didn’t replicate your struct but hopefully you get the gist.