That Jeep Guy XJMJ

i picked this 96 cherokee up for parts and to use as a drivetrain donor. Shell is rusted out and frame is broken. Not the issue at hand but what is challenging me is this starter.
Key on at all and the starter is spinning - not starting - just spinning. So key to run/ start/ turned back for acc and it just spins. I want to troubleshoot this and not just start replacing parts and pieces only to waste my $ on things that don't need to be replaced. So plz don't just comment and say "replace the starter" or "its a bad solenoid". Help me diagnose and troubleshoot to eliminate possible causes for my situation.

Attempts at troubleshooting:
-I have tried to arc the starter w/ a screwdriver and it still just spins-will not turn over the engine
-I have changed out the starter relay and it has made no difference
-ive hit the starter and solenoid with a brass hammer in varying strengths to potentially free up and sticking bits inside with no change in function
-I have seen similar posts/threads regarding the fuel pump relay affecting the starter so i have swapped out that one also with no change in behavior

Jeep is missing the alternator but i didn't feel that should make a difference in starting- obviously no charging "uhh duurrrr"

What else and what other ways can i diagnose this issue?