One of the fundamentals of singing is to understand that the process of learning how to sing takes time.
First, the muscles. They must develop and coordinate, like going to the gym and working out. We start with less weight and make sure that as we do the exercise that we keep healthy form. As our muscles get stronger, we increase the weight and/or the repetitions. Similarly, in the voice, healthy muscular development takes time.
Second, the mind. Our brain comprehends what it comprehends on it’s own schedule. This comprehension is related to what we are able to hear and feel. As we hear and feel more, as our muscles work better, our mind can understand more, often with those lovely little aha moments.
Have I said time enough? It takes time.
Bottom line: nature cannot be rushed or forced. Consistent correct work over an adequate period of time is the only way!