No crank no start issue

Hello, do you have power down at the Starter Motor?
I will pull up the Starter wiring diagrams for you. And this is a Ram pickup truck?

Below are the Starter Motor circuits. Everything highlighted in yellow should have power.
The red wire on the Starter should have power even with the key off and the brown wire coming from the Starter Motor Relay should have power (12volts) during cranking.
If you suspect the Engine Starter Motor Relay is at fault, try swapping it out with another with the same part number. There are usually a bunch of these relays that are the same in the under-hood fuse/relay box.
The Park/Neutral Position Switch Grounds the Starter Relay.

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Okay, if you take out the Starter Motor Relay, and during cranking you should have power (12v) on two of the four female pins where the relay should be. Just touch the pins lightly with a test light, don't shove the light into the pins and spread the terminals.
Next you can hook your test light to Battery Positive and the other two terminals of the relay should light the test light (showing Ground). Quick and easy test,
this will give you direction for your next test.