I know an excellent project envelop.is, which is a cross-chain solution based on the principles of decentralization and openness, and serves to assess (collateral) value of NFT-assets of any order, including synthetic ones. With the help of this service you will be able to make full registration of NFT turnover of any order, for example
cNFT, as well as NFT-transactions of any complexity (issuance, packaging, etc.).