If it’s spawned dynamically by the LB, you already have the reference (return value) and there’s nothing to cast… It’s an actor with the correct type already.

So what exactly are you trying to do.
I want to access some variables,
The LB needs to know variables of the actor, sure - right click the Return Value pin and promote to variable - that’s the hard actor reference now. You can use it as is, no need to cast.
All what’s needed is to access and
change the root Data so that the
instances will inherit that Data
Not sure what that means. What’s root data? Class Default?
But I feel I’m missing the point. Consider describing the end result. No idea why the question is about casting in the first place, there’s no casting needed here.