Starter location

The starter is located under the truck, above a catalytic converter, and near the transmission. I have attached the removal procedure, captured from AllData. Installation is the reverse.

It could be just a loose electrical connection. I would check the battery cables and make sure that they are both super tight and clean. Here is a general guide on doing that: https://www.2carpros.com/articles/everything-goes-dead-when-engine-is-cranked

To me it really sounds like your starter is wearing out. You can try jumping it. Even though the battery strength is good, this will give you a few extra amps and might get it to turn over. Or you can have someone tap the starter with a mallet or other blunt object while you turn the key. If either of these things work, then you will need to get a new starter installed.

Here are a couple of guides to help you get the job done:

https://www.2carpros.com/articles/how-to-replace-a-starter-motor

and

https://www.2carpros.com/articles/jack-up-and-lift-your-car-safely

Please let us know what happens.

Cheers, Ken