Understanding what you are doing, is highly overrated
Understanding can be a delay tactic. Those that want to learn to swim will jump into the water. Those that don't really want to learn, will want to "understand" the water before they jump in. The downsize of not knowing want you are doing is that you feel stupid. Get over it, it is the cost of learning something new! The rewards are that , if lucky, you will have built something that never existed before. This is such a rush and far makes up for the feelings of inadequacy you had at the beginning. The problem is, the first time you get to feel stupid with no clue of what success will fell like. With each new project you have the memory of previous successes. More projects, more previous successes.
I will not ask anybody to be comfortable with not knowing what they are doing, but I do ask that they be comfortable with the idea of being uncomfortable not knowing what they are doing. After 35 years, I am at the point that if I don't feel uncomfortable with what I am doing, I am most likely getting bored. So little time and so much to learn. So jump in, the water, it's fine!