could be

I would pull the #6 plug and inspect with a fine toothed comb, a hairline fracture in the insulation can cause it to arc outside the cyl and not run right. This can happen if you over torqued it at all or if it was even dropped before you bought it.

If all is well with the plug, switch coil packs out. I.E. change out 6/3 with 2/5. They are the same so IF it is a coil pack, this will make the problem jump to cyl 2. Should you do this, just make sure you take into consideration, MOVE THE PLUG WIRE ACCORDINGLY... if you leave them alone and just change the location of the coils your engine will run even worse... if it runs at all. *No responsibility for this either* Backyard Performance 101 advice here.
You will need to clear the DTCs and recheck them after to make sure it DOES jump, if so you have your answer

Good luck