it would be worth taking a sample of higher value tokens that are not minted by OpenSea. probably the vast majority of those tokens are spam or bots trying to capitalize on existing web content like DeviantArt database.
better platforms like Manifold, Foundation and Zora are already using IPFS or Arweave
OpenSea engineers should be shamed for their use of HTTPS URLs in contracts, but it is not the norm outside of their minting platform.