I think the method is fine, you've just skipped a couple steps...if Iam understanding you correctly....
are you with her and then walk away calling her hoping she'll carry the object or is she far away and you want her to carry the object to you when you call her?
can she pick the object off the ground and hand it to you yet?
Iam teaching a hold and carry right now too.

I first taught a backchained retrieve to my hand.... then I started running away from the dog while he has the object, and once he could do that, I started telling him to go to his place with the object and at that point I added the cue to carry the object "bring it" and then a destination "your bed" "your crate" etc

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this is how you backchain a retrieve
Keepers - Shirley's Retieve
but I may be misunderstanding you