Still, Dalinar killed Kalladin in the garage, he grabbed Vin’s head and threw it, or used a tool, or dropped it to put it outside the garage, tje group either didn’t notice him or simply ignored him, due to the message at the door, Shallan was either misled into thinking Kalladin’s dead body was Dalinar’s or lied about it being Dalinar for his own personal reasons, which I have no obligation to figure out. Just because he wasn’t Dalinar’s accomplice that doesn’t deny he was Kalladin’s accomplice. The group found Vin’s head and is irrelevant whether Dalinar left the garage or not after that.
Let it be known that to destroy the foundation of this theory you must say in red: “The group saw Dalinar’s dead body inside the garage before seeing Vin’s head” or “Dalinar never moved Vin’s head outside the garage”
And, Kalladin and Dalinar were both alive, Dalinar moved Vin’s head and was killed before his body could be examined or during the examination.