I have a good friend that I have known for over 30 years that builds motors for a living. It's unbelievable the stories that sometimes come back when there are problems.
He has had people install the engine and not add water and/or
oil. No fan belt so the water pump does not work. Some have trouble setting the timing, and then crank and crank and crank the motor over. Then they wonder why the cam goes flat. Others get it started up, and rather than break in the cam correctly, they let it idle so they can listen to their lumpy cam, which then loses it's lumps.
I could go on, but I think you get the idea. At first most of these people also blamed the builder.
I'm not saying this is the case here. Just that there are other sides of the story sometimes.