BALLSS

did you get a "build sheet" showing what the bearing clearances were??

yeah getting it fixed is the priority...blame game can happen once all the "facts" (verified) are in

can't tell now wtf that rod bearing clearance was..maybe it was fine. If so you do need to confirm why it spun so it does not have a repeat performance of that

right now builder is saying not him..and maybe it isn't but that is why you need to confirm on your end what caused this

The oil analysis will be strong evidence one way or the other