If you need to move the file between an iPhone and a Windows PC or Android device without a cable, use Snapdrop. It works through your local Wi-Fi network and does not require an account. Troubleshooting "Long Piece" Downloads
If you have iCloud enabled, visit iCloud.com on your computer, sign in, and download the video directly from the Photos section.
If you are downloading to a Windows PC, you may need the HEVC Video Extensions from the Microsoft Store to play the file, as modern iPhones record in a high-efficiency format.
For transferring between Apple devices, AirDrop is effective for large files as long as the devices remain close to each other throughout the transfer.