RF Cable Loss on PCB
Indeed you are missing cable loss, but that's going to be a few dB at most, not anywhere near 79 dB.
What you are missing is noise. The receiver sensitivity is the weakest signal that can be received with zero external noise. But unless you have a cryogenic LNA and a highly directive antenna pointed at something very cold, it's going to be external noise, not receiver sensitivity, limiting your performance.
On a cursory read, it looks like table 12 of the datasheet specifies the required SNR at each spreading factor:

You'll have to estimate your environmental noise to calculate the SNR for your link budget.
That said, as Marcus Müller notes in a comment, these modules may not be able to keep up with the doppler change, and the link budget may be the least of your concerns.