If you are not suffering from metabolic disease the blood sugar spike from rice in sushi has no ill effects on your health.
You are eating it with fat and protein from the fish. That also lowers the glycemic load of the meal.
Technically, if there’s no rice, it isn’t sushi Sushi means vinegared rice.
Adding lots of fiber can help slow the absorption of sugar into the blood (no spike). A great source of fiber is avocado which I like on sushi. Whole grain brown rice is good for the same reason, I’ve heard.
As others have said it’s okay to eat rice. I like to mix up my meals with sushi, sashimi and Naruto rolls (it’s a rice free roll that used cucumber cut to form the roll. I personally find using cauli rice or other low carb substitutes really gross.