I have been using Unity on and off for about a year now. I never used a game engine before. I am very comfortable with C and C++ programming though. I did not pay for any classes. I mostly went through tutorials at
https://unity3d.com/learn/tutorialsdid some google searches and watched youtube tutorials. I actually started with Unreal but it did not import complex CAD models easily. Unity is ridiculously easy to learn. I mean the learning curve is not steep at all. On the other hand it has an enormous number of features so you're not going to learn how to take advantage of most of its features overnight.
My suggestions to learn Unity is to pick a project you want to do and jump in. Implement what you can, then read up, implement some more and repeat.
The courses you mention look interesting though. If I have time (doubtful) I will go through them. Maybe I will pick and choose. Another game making resource I like which is a bit more low level is this
https://handmadehero.org/
