blackbeans

You must be an American. Stone or concrete walls are normal in many countries.

Youn can indeed use a hammer drill to drill holes. You can buy them for as little as 30 dollars these days. And you can use an angle grinder to make cutouts for cables/tubes, and apply plaster afterwards.

Many houses in the colder regions already have cavity walls with insulation in between the walls regardless of the building method, so I don’t think this method is very wasteful in amount of material.

However, I agree that 3D printing houses had various downsides, such as the weird corners, inflexibility to modify/expand/repair after the initial build and potentiality worse insulation characteristics. I am more of a believer in prefabricated houses, where building houses becomes an industry instead of a project.

69 MOhm is not very likely in a larger housing. Resistors can shift in value but they rarely break without any visual damage.

I would first check for broken solder joints on parts that get warm and check if the relay is performing as intended.