Husk
To me, there are a couple of aspects to your situation. Learning to fly the plane is problematic, but not insurmountable. The faster, more powerful and more complex, the more there is to absorb. This is why it is so important to have a Mooney specific instructor, knowledgeable about the plane you are contemplating. But, no matter what, you will eventually get that all sorted out. My first plane (ownership) was/is a 231. It took a while with engine management complexities, etc.
However, the more troublesome aspect is the judgement necessary for true piloting. An instructor can definitely help in showing what to look for, but the real learning (in my opinion) has to come from doing it. Flying in good weather close to home, like what is typically done in training, simply doesn't do much for getting one ready to take on "traveling" by plane. Unfortunately, the only way to learn that is by doing it. And it takes a lot of hours. There are no shortcuts I am aware of. The really tough part is that in order to advance, you have to continually push your limits. But if you push too much, it gets very dangerous. So balancing that advancement/safety issue is what takes all the time. Continual training and patience is the key.
Just my opinion. Others may disagree. Or maybe I'm just slow to learn.