Maybe check out Tailscale. It's mainly a mesh VPN for your own devices, but they have a lot of options included so you can share stuff with other people.
I've set up tailscale in the past week and fallen in love with the ease of use. So, this has my vote too. But, if i was doing this, i would chop the file into, say, 500mb parts using 7z or WinZip and then transfer it through SCP (WinSCP if using windows) over tailscale IPs.