Correct, IPFS is not a blockchain - while both are merkle-dags ('directed acyclic graphs' of hash-linked data), blockchains have all nodes sync the state collectively, while IPFS instead shards state across the entire network (such that each node maintains its own filestore).
How is IPFS related to blockchain? On a technical level that is.
AFAIK IPFS is somewhat related to FileCoin which runs on "a blockchain". But not IPFS.
Or am I missing something?