I had aphantasia and then taught myself to see images too.
It’s possible aphantasia is something like deafness but there is no way anyone knows for sure either way.
People who think aphantasia is definitely similar to deafness probably are falling into the “efficient market hypothesis” trap. People assume scientific-sounding or clinical terms accepted by official sources are scientific. In reality, these official sounding (and even officially endorsed) terms materialize through domain-consensus which is different than the scientific process.
Domain-consensus allows for “magic words” that can’t be broken down into parts the same way something like deafness can be broken down into the material biological mechanisms that causes them. Psychology is a mind-field of these magic words because we have not yet unlocked mechanistic interpretability of the brain (the same way we are now trying for computer neural networks), and rather than breaking down categories of diagnoses into the behaviorisms we can observe (which many practitioners have had real-world success with), the academic and professional field has a culture of deferring to magic words/mechanisms that we can’t observe.
Regardless, nobody can know if aphantasia is a skill issue or immutable. My instinct is that most people probably blame having aphantasia when they don’t have it the same way people say they were born “not good at math.” However, it’s possible (although not necessarily true) a small portion of the population actually has it. There is no way to know for sure unless we understand the brain mechanistically which may be never.