OK, see my much later reply in the other thread (or move it here if that’s something you can do). As stated in detail there, you are confusing adjectives of quantity with adjectives of degree
ETA the key section is this
Adjectives of quantity such as ‘much’, ‘more’, ‘less’, ‘enough’ and so on do use ‘of’ - e.g. ‘enough of a problem’ and ‘too much of a stretch’.
But with adjectives of degree such as ‘good/bad’, ‘big/small’, ‘long/short’, ‘little/large’ and so on, ‘of’ is not used in standard English. E.g. ‘too large a box’, ‘not that big an issue’.
