Sounds like IPFS to me. Why not just upload blobs to IPFS instead and skip the extra dev work?
Discussion
I had the same question, but according to https://docs.ipfs.tech/concepts/content-addressing/ IPFS also uses SHA256 (at least "by default"), so *I think* you could use the same ID and let the client choose whether to get a file from a Blossom server or from IPFS. Would be great if OP can confirm though.
Would have liked IPFS