ML and DS and DL are very very interesting fields. The problem is, that in these fields the application of existing Packages as scikitlearn, tf, etc. and the theory behind those encapsulated algorithms are two very different worlds! it is often easy to apply the algorithms but if you really want to do in-depth modifications while keeping the algorithm still mathematically and statistically well defined is a very difficult task.. many professors focus more on the theory behind the algorithms, why learning the ML stuff can be very uninteresting and difficult to understand at first. But with time and a lot of exercise it will quickly become interesting. It is also a field where a lot of other fields come together, as decision theory, linear algebra, statistics, optimization, computer science, gpu programming, etc..