What about
FName name = *requiredComponent->GetName();
FString base = name.ToString();
int32 index = someIndex;
base.append("_");
base.append(FString::FromInt(index));
FName newName = FName(*base);
What about
FName name = *requiredComponent->GetName();
FString base = name.ToString();
int32 index = someIndex;
base.append("_");
base.append(FString::FromInt(index));
FName newName = FName(*base);