How to correctly store and retrieve firebase storage URLs in firebase realtime database

I only started to use the join block after seeing some tutorials here at the community.

I am already using the replace block to be able to make it work:
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But when I use do it block within downloadUrl in the upload success block, I get the URL correctly, without " or \

But even if I can make it work I would like to know how to store it correctly. I don’t understand why these characters appears in firebase realtimedatabase