I saw that a Telegram clone was being worked on, but I wonder if it may have fallen off to the side because the links that I tried don't seem to work anymore.
Are there any other apps that let you share files?
Nostr is a JSON-based protocol, unless that changes for another serialization format, it is suboptimal to store binary content (you'd have to encode as base64 or something else, but it will have to be packed as a valid UTF-8).
You could however use for content-like distribution, an unstoppable one, and upload the files to a Torrent or ipfs.