How to add a layer to an image?

Question

Unity

I have several prefabs, their design was originally like this

canvas (environment)
-- Object
---- Image
---- Text

After it became necessary for me to set a specific layer for each, I read that they then need a separate canvas and the design became like this

canvas (environment)
-- Object
---- canvas
------ Image
------ Text

layers are set and so far no problems (sort of), but how will it work when there are more than a hundred or even thousands of them, is it right to set them like that?
I emphasize that these prefabs are created statically (at the beginning, with layer 1) and dynamically (during the game, with layer 0, they fly to the target and are destroyed).
Is it correct to use them this way or should they be used differently? (otherwise everyone has their own canvas...)