Until more is known about the various EV electrical systems, it's currently a best practice to have a professional shop research your components and their electrical connectivity needs. They (reputable shops) have liability policies, or at least they should, and you really should validate that...
Seems like using a pair of crossovers for the separates would work better. For example, your rear-left amp outputs wire directly into one crossover box, which has 4 output wires with crossover filters built in. Those outputs include the positive and negative wires for your rear-left soundbar...
You may have dislodged the plug or plugs that plug into the gateway on the back of your driver's side kick panel speaker box.
Check those when you have a chance.
I might recommend downloading the PAC manual for that device. It'll give you a better understanding of the install procedure and settings/capabilities.
Scan the manual really well for the PAC. It's a bit confusing, especially the calibration process and dip switch settings, but focus on the extra wire dongle. That is where you would feed the speaker signal back to your stock speakers.
For what you're describing, it does seem like the PAC and the gear you describe would be a good option for you. Let us know what you end up doing, and good luck with the build!
Regretfully there's not an easy, straight-forward answer available here because of all the vehicle, and country specific issues researched for the Wrangler.
I do believe the answer lies with adapters made by PAC. https://catalog.pac-audio.com/catalog/amppro-amplifier-interfaces/#
I have to...
That's the best part about the PAC, it plugs in inline with the existing plugs. There is a wire dongle that comes with it, and as I understand it, that is where the output wires from your amp go.
Download the PAC manual, and you'll see what I'm referring to. Beware, as it's not the easiest...
;) That's why we're here! Just don't want you to go through all the trouble and not enjoy the end result. Jeeps are loud, and require a bit more clean power especially if the top is off/down.
I try not to make too many equipment specific recommendations, mostly because everyone tends to have...
I believe there are adapters, at least I think I've seen a few, though I just haven't used them. Metra is a brand that usually makes those.
For sound quality, my concern is tied to how much the stock system is already equalized. The cost of that DSP/amp is just over that of a really good DSP...
Gotcha', sorry I assumed you wanted RCA level outputs.
I know you didn't ask, though I simply can't recommend that product. If you've heard it, and have experience with it, please share, but that device doesn't seem like it will offer much in the way of power/sound quality. I really don't...
If simplicity is what you are looking for, the PAC device will be your best bet. There are other adapters, but it sounds like this might be a good path for what you are looking to accomplish.
May be worth trying. Since you are pulling a stock line signal, it could be overly sensitive. I don't run a similar setup and am unable to test it.
It could simply be a norm when not using a DSP or more advanced LOC. Please share what you find, and good luck!
Those are El Cheapo. If you are installing just for looks and a little extra light, they may do, though I wouldn't recommend these unless they are going to be used on a lawn mower.