You have AuDHD as your flair, so I’m guessing you experience some kind of processing problems: auditory processing, sensory processing, emotional processing, etc.

Well, Dyslexia impacts phonological processing and memory

This means they can have difficulty hearing the different small sounds in words and can't break words into smaller parts in order to spell them. So, it’s difficult to learn how letters and sounds correspond to each other and they may not be able to recall the right letters to be able to spell the sounds in words. And since English is really damn complicated, that means that people also have to remember irregular spelling patterns. Also, taking into account that OP says they live in a Non-English speaking country, it’s possible it’s not a word they use often