All the clothes in my game are based on Kevin's body, so they are all made under the same standard. I started making my NPCs these days, and I chose to use Headshot to replace the NPC's head and keep the male NPC's body consistent with Kevin. I tried many times, and in the game engine, the shirt that fits Kevin does not fit the NPC. After a long time of troubleshooting, I found that Headshot's "Keep Head Size" and "Keep Neck Size" will cause the bones to change (Even if "Attach To Body" uses the "Current" option), And if I uncheck "Keep Head Size" and "Keep Neck Size" and use the "Current" option when "Attach To Body", the body will stay exactly the same as Kevin, but the head will become distorted

Expected Result:
Only the head is replaced, the rest of the body remains the same