My 1st plumbing was complicated (performed to residential code, cause you know I’m basically nuts). I had shut of valves & drain lines & exterior hose bib, brass risers from the HWT.That's a good topic to chew on for DIY water heating systems.
Temp regulation for the shower is a trick I'll need to learn.
2nd time around I went as basic as possible. (See photo above post)
This time my hot water side consists of the “Pex“ fitting into the tank, the pipe (about 15” long), & a “Pex” fitting at the end where the tap screws onto.
The cold side is; male fitting to accept flex hose from the 12v pump, a T, a fitting to the cold side of the faucet, a short pipe to the fitting into the hot water tank ( cold supply ).
Pressure relieve valve is piped thru the van floor to the outside.