[dmsfrr]

Assuming the battery is in good shape & charged. Is there any clicking from the starter solenoid?

Automatic transmission?
The neutral safety switch circuit can prevent the starter solenoid (and starter) from engaging. The original switch may/should only connect when the shifter is placed in neutral.

You most likely have three battery and starter cables. The Plus and Minus terminal cables on the battery and a large cable from the solenoid to the starter. A total of six connections.

There are two often neglected connections. The battery Ground cable connection to the engine and the housing of the starter solenoid electrically grounds on the inner fender or firewall.

There is another ground wire from the engine to the firewall although it usually won't affect the operation of the starter, just most everything else.

All of these connections must be metal-to-metal clean and tight.