Two years ago I got a starter from my local cummins dealer for about $250, has a Chrysler plate on it is a very nice unit. Beats the $400+ ones online all day long. Not a cheap unit really really nice.
My positive cable was so degraded from my oil pan and PS/vacuum pump leaking on it all that was junk. You could have a bad cable, don't mess with the repairs of the ends and stuff, sounds like you have been down this road enough. This is a easy straight forward fix.
I recomend a decent cummins starter and a set of battery cables from Geno's.
If you get into a really bad spot let me know and I can get a new price on that. I'm not a dealer or parts place you can cold call the counter and explain you need a starter, private vehicle, in a bind.... for $35-$45 they can overnight it.
Have you registered your ESN on quick serve do you have the part number for your engine, not that it matters much they will update the number to the most current version.
IMO you won't beat the Genos battery cables they are a buy out product and the info is in their flyer.
Do you have a decent "set" of batteries. Make sure your set is matched and fresh or pick up some new ones. You can usually get some good deals on a set of AGM batteries from numerous big box retailers.
Batteries, starter, cables, done. There might be one more small wire in the starter harness.
And the good news is your starter 12pt 10mm bolts are already broken free, mine were super tight what a PITA to keep messing with the starter, cables, contacts, I also put new bolts in mine.