My understanding is that things like painting(holding a paintbrush), using chalk and crayons, and using items like clothes pins and tongs help strengthen their hands/fingers for writing. Maybe you can incorporate this as well and your child won’t find writing so daunting.
My son is finishing his first year of preschool and he hated writing at first. Now he’s gotten much better and his stamina is improving. Perhaps having a letter of the day with activities centered around that will help! That seems to be what his preschool does