Hi!
Test on UE4.25.3 FString::Format:
const int32 MyInt = 12;
const float MyFloat = 0.12f;
const FString MyString = FString(TEXT("MyStringValue"));
//const FString MyStringPrintf = FString::Printf(TEXT(“MyStringPrintf: {0}, {1}, {2}”));
const FString MyStringPrintf = FString(TEXT(“MyStringPrintf: {0}, {1}, {2}”));
const FString MyStringFormatted = FString::Format(*MyStringPrintf, { MyInt, MyFloat, MyString });
UE_LOG(LogTemp, Warning, TEXT("MyStringFormatted: %s"), *MyStringFormatted);
// LogTemp: Warning: MyStringFormatted: MyStringPrintf: 12, 0.120000, MyStringValue
Hope this helps!