I've almost bought this kit about a half a dozen times lol. Unfortunately I don't have the pre-existing harness so would either have to run the wire forward and tap into the cargo light wire, or possibly just use the trailer wire harness option. I also would prefer to have a switch in the bed like the 2019's do. I considered buying the 2019 kit but wasn't sure if there were any wiring/harness differences to worry about and it also looks like the lamps size might be different as well, so not sure if the holes are the same in the 2019 vs older. I guess I could stop by the deal and look at a 2019 bed.
I believe most have found that using 60" LED strips on each side of the bed will provide better lighting, but I like the factory look of the mopar kit in the bed to be honest, even if it does have less light.
EDIT - now that I actually looked a bit closer an the lights and holes are completely different on the 2019. So for previous years you either have to use the cargo lamp button as designed, or wire in a switch on your own if you want one in the bed. There is a thread on this mod somewhere also.
Here's the link -
https://www.ramforum.com/threads/finally-installed-bed-lights.119108/#post-1712576