Here's where connector 301 is. (304 is your button)

 

Finally some good news.

I traced the trunk button wires starting at the junction area inside the trunk and found no connectivity on ground wire. I took out the harness and de-loomed it and found the broken ground wire before the flex boot. No idea how that could have broken there.

Not a waste of time to check the whole harness because I found another area after the flex boot where insulation was completely worn away and bare wire was exposed, and upon close inspection of the wiring at the flex boot I found a wire hidden in the bundle that was only holding on by 1 strand (backup camera wire).

Fixed them all up and good as new, everything working.

For giggles I tried my old trunk button and it did not work.

So figure that one out for bad luck - a bad trunk button. A bad junkyard trunk button. A broken wire outside of the flex section and a wire about ready to break inside the flex section not related to the trunk button.

 

90-odd% of the time any electrical issues related to the decklid are going to be tied to that flex boot.

FWIW, good troubleshooting on your part and I am glad that you were able to resolve the issues entirely.