2016 Dodge Journey - Big problems after new Transmission

I swapped transmissions an now I have a no crank no start issue

Has your shop measured the input voltages to the starter motor during cranking attempts? It won’t crank the engine without the proper input voltages.

Is this a brand-new tranny or one you got from the junk yard? If it is one from the junk yard, then it could be a bad neutral safety switch (Transmission range sensor).

Observe the transmission gear position indicator in the instrument cluster while shifting through each gear to see if the range sensor input is correct. If the transmission range sensor is disconnected or damaged, the PCM won’t allow the starter motor to operate.