Itachi is indeed a much hyped character but his hype is repetitive, different characters saying the same thing over and over again, gaara does have his chances
some people wont agree about sand eye being immune to genjutsu but i would point out that the sand eye can be formed anywhere, it can be formed behind itachi, it can be formed hundreds of meters up in the air, it can even be formed behind a boulder or tree
You must be registered for see links
so unless itachi has sharingan at the back of his head or can cast genjutsu through a boulder he can forget about using genjutsu on the sand eye
not even muu, a sensor detected it, only gaara's father could detect the sand eye of gaara (he used the same technique against in life)
so genjutsu is no problem at all
gaara was still able to manipulate and sand even after it got hit by enton which is much hotter than regular katon jutsus so neither amaterasu or katons would do much good to itachi
amaterasu also isnt hitting gaara when he is in air surrounded by his gourd sand in a spherical shape, he wears a sand armor anyway
susanoo cant reach him in air except for yasaka magatama which can be dodged
other minor jutsus of itachi like clones or ninja tools arent worth much against a wave of sand