how do i download photos from iphone6 w/no internet connection?

Your iPhone is running a too old of a system for Photos V8 (Ventura) to be able to work.with it. You'll need iOS 12 or 13 to be compatible with Ventura. The bottom line is that you'll need a new iPhone.

You might try AirDrop to get photos from your iPhone to your MBP.

Or connect your iPhone to the MBP via its USB charging cable, open it and then launch Image Capture. See if Image Capture can see the iPhone. If it can you'll be able to download to a folder on the Desktop and then into the Photos library.

I am not a Mac user, however for a PC, the phone should be switched on and then it will ask you to confirm the connection keying in your pin number and trust device. I guess you have an icon that shows all drives? If you can't make it work ask a friend with a PC running windows.

Plug a USB cable into the PC and then look at My Computer and you will see the drive etc