Transfer file from iOS to macOS without internet, natively?
If the file in question is a large video or image file visible in the Photos app on your iOS/iPadOS device, you can connect the device directly to your Mac via a cable (Lightning and/or USB-C on iOS/iPadOS device, USB-A or USB-C on Mac) and use the Image Capture.app on your Mac to directly transfer it.

If it's a file stored in one of the apps installed on your iOS/iPadOS device that supports File Sharing, you can again connect the iOS/iPadOS device to your Mac directly via cable, and use iTunes (macOS Mojave and earlier) or Finder (macOS Catalina) to directly transfer it.

If none of the above applies, and your large file is accessible via the Files app on your iOS/iPadOS device, you can use a removable storage media, to transfer the file natively.

iOS/iPadOS supports transferring files by connecting removable storage. Invest into one of the USB-C or Lightning removable storage device. You can even find some listed on Apple Online Store:


Storage - Mac Accessories - Apple


Example:


SanDisk iXpand Flash Drive Go: 256GB, 128GB, 64GB.
SanDisk Ultra Dual Drive USB Type-C: 128GB, 64GB.


The same or a similar product can be connected to an iOS/iPadOS device, and Apple's Files app can be used to transfer the file to and from the storage. The same can also be connected the a Mac.


Connect external devices or servers with Files on iPad