OpenSea smart-contract (mainnet or Polygon): This will not use our db at all so we will create a new code logic to fetch the metadata, and we could decide which logic to use (old one on Rinkeby, or new one through their API) depending on the env or MetaMask network.
This also depend on #72.
https://c8-nft-default-rtdb.europe-west1.firebasedatabase.app/titles/0.json
https://c8-nft-default-rtdb.europe-west1.firebasedatabase.app/<NETWORK>/titles/0.json