Multiple channel transfer only works when you are transferring either to or from multiple peers. For example, in the case of a fully seeded Torrent, you're downloading from sometimes hundreds of different sources, each one giving only relatively small amount of data and using a relatively low amount of bandwidth. All those small bits coming together into your computer at once results in a very high speed download only at your end.
If you're transferring a file between yourself and a friend, you're probably only looking at one computer at either end, so you will not get the multiple-peer, maximum bandwidth utilization of a popular Torrent.
So if you can't get the multi-channel, you're left with "free" and probably hopefully easy.
In this case you'll need to configure your firewall and router, and probably install software to facilitate the transfer.
The most mature and direct method that doesn't require any third party apps or cloud hosting will be FTP.
Using a free tool such as FileZilla (which is multiplatform and free), which is an FTP client that also has a fully functional FTP server, you can "host" the file on one computer and allow the other computer to connect and move or copy the file using the maximum available bandwidth of the slowest connection of the two.
However, as alluded to earlier, personal firewalls and routers and modems block this sort of thing normally because FTP servers open to the internet are not usually things you want on an average user's computer. So you'll need to configure your firewall and router and probably modem to allow this transfer.