think of kurama as a huge water tank
Naruto, has a huge pipe coming out of the water tank. NAruto giveing chakra out, is like adding more much smaller pipes. The water is drained slowly, whether or not the valve is on or not, because there is a leak. The water is like kuramas chakra. The tank can be used until it is empty, or you can stop and close off the tank for a bit, and refill the tank
So in narutoverse terms, naruto shareing chakra does not make him any weaker at all. Simply he has less kurama chakra to be able to use(So basically, lets say he gave out half of kuramas chakra to the shinbi alliance. With full kuramas chakra, he can use 200 rasenshurikens. Now that he has given out half the chakra, he can only use 100 rasenshurikens. The rasenshurikens power is the same, only he can do more of them, without shareing the chakra)
that is the mechanics of how kuramas chakra shareing works