intermittent starting/battery issue

This issue started before I took everything apart, so it's nothing i touched under the hood when I removed everything to paint. I'll go to start the car and the warning lights come on, but as soon as the key goes from the accessory to starting position, everything goes dead. To start the car, I open the trunk, disconnect and reconnect the negative terminal using my quick disconnect, and the car will start with no issues. I've electrical taped the metal near the quick disconnector so i don't think it's touching and grounding out, but not sure. I also have noticed on the negative wire, that the grounding point partway down the cable is pretty frayed. My question is could it be due to the fraying, in which case I'll replace that, or possibly something related to the quick disconnect?

I would try cleaning the battery cable clamps, inspect for corrosion up the battery cables, and maybe add an extra ground at the battery and one from the engine to the frame.
Also pull the battery itself. Check the water levels (if you can), charge it, then have the battery discharged checked at the Auto Parts store.

If it is still a problem try bypassing your disconnect switch as a troubleshooting step.

it's a brand new battery, so levels should be ok, will check the other items. thanks!

I'd replace the frayed cable first - split cables isn't something I'd want in there anyway. I know of people who have had battery cables disconnect or rattle loose when on the track that shut the whole car down at over 70mph. Not quick, but sketchy sh*t to deal with when the PS and ABS lock up on you mid corner....

It's possibly either the coil pack or leads, especially if they've never been replaced...