Just a quick update, I’ve figured out what I want to do with the water heater. I bought that pictured thing, which I believe is a spare part for a water boiler or something, costs like $13. I’ll do wiring myself, so I know for sure that it won’t electrocute me. This image shouldn’t never exist as a commercial product. Search on Aliexpress, led me to products that has a DO NOTE TOUCH DURING USE warning in their description. And it’s a 3000 Watt water heater, insta death. I’m done with those cheap-ass water heater.
Putting it together was simple enough. Put AC wires in, ground included. It has a DN25 pipe thread, so I just design and print a thing with that thread to surround the exposed wires, and enclosed it with epoxy resin to waterproof the wiring. Works like a charm, completely submersible, no more splodey things. And it’s 1500 Watt.