Are you sure UPX actually beats the standard layer compression which is already provided? After applying UPX, the result should be nearly uncompressable, so if

Are you sure UPX actually beats the standard layer compression which is already provided? After applying UPX, the result should be nearly uncompressable, so if UPX performs worse than layer compression then it might be better for network usage to not use it at all. In this scenario where you are unpacking it in advance, that eliminates the main benefit of UPX which is that it is self-extracting.