If you had lived your life from the McDonalds dollar menu, and then then someone ga,e you a gourmet meal... you might be hesitant to try it yourself.
the first priority is to make sure they are eating at all, and then to move them over to the better food.
my big issue is that I have small fish, and it's difficult to find suitable food that they can fit in their mouths, pellets can be a little too big and hard at first for some fish, if you see them try to eat it but spit it out, maybe wetting the food before dropping it in the tank would help to soften it a bit.
My personal preference recently has been for NorthFin food, You can get samples of up to 7 types of food from Super Cichlids..
https://www.supercichlids.com/collections/frontpage/products/northfin-samples
(I think you have to pay shipping, no idea what it is)
I have had good luck with Fry starter, Krill, and 0.5mm community
HTH