Bad comparison, apples and oranges are two different fruits. Chakra and stamina are practically the same thing, they are synonymous. You are the one who is not understanding, it is not a question of having more instances, but that you did not understand the point, chakra and stamina are synonyms, when it is said that everyone has chakra, means everyone has stamina. Now let's go to the logical part of the thing: Why do I say that do they refer to stamina? simple, it's because the shinju absorbs the "life force" of common people and animals that don't mold chakra, and as shown in the examples I sent, the chakra net is only full after the person molds the chakra by uniting the two energies, if they do not do this, the net are empty, because the chakra itself does not yet exist as new energy, but does exist in its primary form (physical and mental energy). After gathering this information, this is the conclusion you come to: