I've never read anyone say what they mean by "visualize" when they say they "can" or "can't" "visualize". The people who say they don't "see" anything, don't explain what they mean by that, and the people who say they can visualize use the word "see" without explaining what that means. My suspicion is that people are referring to different things.
No one is born "literate". They learn to read. Since people are forced to learn to read, it's treated like an ability, rather than a skill.
No one is born "able to" ride a bicycle. They learn and often are forced to learn to ride a bicycle. When someone "can ride" a bicycle, it means they developed the skill to the point where they don't need to think through the steps of riding a bicycle, because it becomes part of muscle memory.
The "literate" person or "bicycle rider" is different from other people by degree. People are better or worse at it, not able to or unable to.
If you draw, you are visualizing. If you describe something, you are visualizing. If you can recognize a letter, then you can "visualize". I've watched videos of people saying they have Aphantasia, demonstrating how they visualize, without realizing they are visualizing, apparently.