> So in my free time I try to learn to be a full stack developer (they -- the school -- learn you to become this) and the most part I hate is the front-end one, nothing wrong with HTML, CSS is easy but hard to master with it; and I lose interest in the back-end part, web frameworks, React, Ember, Vue [...], I know they made the work more easier, it's not for me.

Sounds like you are not swayed by the hype. Good! Most of the websites using these frameworks do have no actual need for them. Most even render merely statically renderable content without actually interactive widgets. However, it would probably be difficult to find frontend jobs without parading any of the hyped frameworks on the CV.

Fortunately there are many other things for a software developer to do in non-frontend jobs.