Swipe up = from inside to out = from me to the person infront of me.
Swipe down = out to in = the person infront of me to me.

To right / To left would be transactions/settings for either sides (most apps have have the burger menu at left or right, some with a swipe to right or left to view it. ex: amythest).

The send screen would open up the camera immediately at full screen, however, at the bottom of the screen there'd be a field with a button to add an address (both option options active on the same screen). saves a tap or two with this design I'd imagine.
If the user scans, or inputs an addresses, it switches to amount + confirmation screen to send.

NFC scan is always on while the app is on or running in the background, so that's a direct to confirmation screen.

Swipe down would show QR + copy address + field for custom amount with a button to re-generate QR with that amount + copy invoice button.