Let me explain.
In order to draw convincingly, you must first internalize the object in 3 dimensions. You have to learn how to "think" in 3D - more specifically, given an object, you must be able to draw it from any angle, with or without foreshortening, and with any arrangement of illumination and with any camera focal length. Start with simple shapes - they're boring but that is a __must__. Then, start stacking primitives such as cones, cubes, cylinders, etc. Draw 20 different views of the same setup of primitives. Do this everyday for 6 months and you will pickup how to think in "3D" so to speak.
If you follow , you won't be able to do this. You will be able to copy a photograph or illustration by recognizing shapes but that only goes so far. If someone asks you to draw the same thing from a slightly different camera angle, you're lost.
Learning how to paint then adds another layer about color harmony, texture and stroke style. But fundamental drawing skills are __critical__ in order to paint well. All bets are off if you're trying to do abstract art or non-representational art.
You can take Jeffrey Watt's classes or a full course  or follow a few channels such as Sycra  on Youtube.