I have a few ideas to improve blossom, but none that will make it able to support "large files". the fact that a whole file is hashed using sha256 is the main bottleneck, it means the larger the file the longer it takes to hash and the longer it takes to verify (possible attack vector)

Ultimately for "large files" BitTorrent is the best solution and will probably remain that way. which is why we have NIP-35 torrents on nostr 😁

I say "large files" in quotes because every user and every server is going to have a different upper limit on file size. for example a blossom server on my local network could probably take a 10Gb file while one over tor could only take a 50Mb file