Hello, I do have a few thoughts. About getting that element out, here’s what I’ve had success with (even without getting a patent :D). Take a 1-1/2″ six point socket with a 3/4″ drive and grind off the end of it so you have full contact with the element. If you look, you’ll see that sockets are beveled inside, so they don’t make full contact. Removing that 1/4″ or so fixes the problem. I’ve snapped off 1/2″ drives, so I use the bigger drive now. Oh, and this: always put two or three turns of teflon tape on the element before putting it back in. This will make removal the next time much easier!
About that red PEX line, I’d like to see a photo of where it ties into the heater. That will give us more to respond to. It may have something to do with the heat pump, or a recirculation line or??? Also, how old is the house. Knowing that will be a clue about the use of PEX. 😎