Before yall get mad at how ive treated this jeep, i was in college and when i start my new career im gonna be swapping almost the whole drive train and accessories.

So, I got a 170k mile jeep 4.0l last 20k miles it's been pretty rough sounding. Just trying to keep it going till it dies outright and I'll grab another 4.0l from atk to hold me over

Anyways, there are a few more problems but I decided to do my oil change today, just typical oil only no filter yet, I'll save that for another 3k miles. But when I emptied it was not only low, (has had this issue for a long time), but my magnetic drain plug had the typical small amount of glitter, plus a piece of metal the size of a grain of kosher salt. Got my oil changed at wally world so idk if it's been there for 10k miles or within the last 200 because within the last 100 miles I've noticed a whining sound on startup, once it warms up though its usually gone. Oil pressure is always good, never dropped, so I'm thinking maybe from a cam bearing? I'm not sure. Or how worried I should be. I have a motorcycle to get me around daily driving once the weather warms up so I can save the $3500 or so for a new engine once this blows, but how worried should I actually be?

I'll be replacing the serpentine belt tomorrow too to see if that gets rid of the noise right away, couldn't pinpoint the sound when I had the hood opened