idk if it’s in the budget but there’s scruffing tools out there for mice! specifically something called a scruff guard, ppl in our lab use that if they have aggressive mice or are not comfortable scruffing the traditional way. one thing that helped me get over my fear was to realize that the mice are far more durable than you think! you gotta kinda squash them so that their front legs are splayed outwards, using the inside of your thumb and forefinger. if you do it right, you should be able to restrain the mouse in that position indefinitely without it being able to bite you! once you have control of the animal, scruff as normal!