Yes, you do have to actually learn how to use an engine, just as you had to learn how to use SDL or any other library. Most people, once they learn how to use such engines, are far more productive than people writing entirely low-level code. You can have a basic 2D or 3D scene ready in Godot in minutes, with collision detection, lighting, camera and a controllable player. from scratch, the equivalent of either might take days or weeks.
I'm not disparaging low-level coding here, I write projects in C, LuaJIT and SDL myself. But I know from personal experience how liberating it can be to not have to deal with 90% of what amounts to uninteresting boilerplate and focus on the actual creative part of a project.
Your comment reminds me of when I participated in a game jam one time irl. A lot of other people were using existing engines and there were some pretty cool results that different groups had.
I worked alone and used SDL. This was also one of my first attempts at making a game.
I managed to make a couple of command line inputs and outputs in the terminal, and then use SDL to render a single sprite on screen that did not move or anything. Needless to say, my entry did not win any prices :p
I'm not disparaging low-level coding here, I write projects in C, LuaJIT and SDL myself. But I know from personal experience how liberating it can be to not have to deal with 90% of what amounts to uninteresting boilerplate and focus on the actual creative part of a project.