Where to start learning modern OpenGL?

Question

OpenGL

1) 99% of the articles I find are "make a colored triangle", "a rotating cube" and also "draw an owl from circles" with level var x = 1; // присваиваем 1 переменной x.comments , shaders, coordinate system, etc.
2) What is the easiest way to start learning with WebGL or with regular OpenGL? I don’t understand, in Python (PyOpenGL) and in C ++, things like glPushMatrix, glLoadIdentity, gluLookAt, etc. are also used in articles. which are not in WebGL. In WebGL, I need to manually rotate and multiply matrices (I use gl-matrix).
Or the lighting. For OpenGL we turn on light glEnable, for WebGL I found an article on how to do it manually in fragments. shader.
In general, the code is completely different. It's confusing.