It sounds like the only thing that would’ve satisfied you would’ve been for iOS to natively understand whatever the Microsoft system is for broadcasting videos? I agree it would be delightful if Apple and Microsoft could agree on a “I’m a short term drop-point” “send to any nearby open drop-point” API, but the absence of this doesn’t seem likely to be either Microsoft’s or Apple’s fault.

The Apple way to do this would’ve been to send an iCloud email. Apple Mail would’ve uploaded the file to a server, and a short-lived link would’ve been created, to avoid SMTP size limits.

Pretty much exactly what you ended up doing but manually via Firefox Send.