The only way to solve this problem while avoiding opinions and tastes is to objectively look at what you are trying to build.
Thus the most efficient part of your question is your last sentence: you want to build medical software and medical mobile apps.
In that case, the answer is definitely Java, as is for all "real" software projects.
Python is good for data science, in other words for statistics. Its other competitive advantage is that it is easy to learn for beginners, but that would be a bad reason to use it for a "real" software project.
JavaScript is a mess you don't want to get into. The major reason why it's popular is that many people learn it first, because its very basic features are easy to learn, although they don't get you far, and because it used to have exclusivity on the web. But in reality it will make your life a lot harder after a few weeks, without any benefit. I know I'll get criticisms for that, but I stand fully by this position.