How can I synchronize objects that are spawned during the game and become children?

In my project, I made a system, spawning weapons during the game in the hands of the player (making them children). And I do not know how to synchronize this weapon, because NetworkTransform does not work with child objects, and NetworkTransformChild does not work if the object is spawned during the game (it needs to be configured in advance). Tell me, please, how can I synchronize the weapon, are there other ways to do this?

P.S. Thanks to Google Translator.

maybe you can setup all the weapons in advance, then just disable the mesh renderers of the ones that are not active