Starter clicks using the key, engine starts by jumpering the relay

It’s definitely the starter clicking. I can tell because it almost feels like the engine is trying to turn over while it’s clicking. But it doesn’t always click. Sometimes nothing happens when I turn the key.

I know I just need to put on my big boy pants and do some checking, I was curious if anyone had experienced this before. I kinda suspect a bad connection at the bulkhead, because before I changed the ignition switch, jiggling the wires under the dash would help.
You say "clicking," is it just one click, or a series?

A series of clicks or "buzz" indicates low/ bad battery, dirty battery terminals, bad cable, connections, in no particular order OR a LOOSE connection at the starter

One click could be bad starter solenoid, or starter, but that does not explain being able to crank it by jumpering.