Although there are coal and iron mines within Spain, their overall scale is not vast, unable to sustain a very large industrial power.
This is also why Carlo wants to continually expand colonial territories, for the current scale and potential of Spain's mainland cannot compete with super powers like the United Kingdom, France, and Germany.
The scale of colonies that France can exchange with Spain is not much different from Portugal, and the probability of France giving up its West Africa Colony is extremely low, making collaboration with Spain almost impossible.
This actually means Spain has only two options: either collaborate with the British to obtain lands in West Africa and the Middle East, or collaborate with the Portuguese to gain control of the Congo Kingdom under Portuguese rule.
Although the Congo Kingdom can be connected to Spain's Congo Territory, its actual value is certainly not as high as the British West Africa Colony combined with Middle Eastern lands.
