Not trying to pry, but is english your second language?
I assume not, but I have the exact same thing with articles (“the” and “a”/“an”) that you have, except for me it was clearly caused by english being my second (my native language doesn’t have the concept of articles like that at all). And I got much better at it over time too, but it still slips through all the time for me. Less so in writing (even though it still happens not that rarely), but moreso in speech.
I have trouble reading when I’m tired. Or fully awake making out handwriting.
I have many years of practice adding a’s, the’s, and you’s - people will ignore everything you write if you come across as mentally subpar.