How can I try new dof foods, hurricane Ian wiped our home out and well, financially we're strapped yet I've spent soo much money out of my savings trying to find Charlie kibble he will eat. He JUST turned two on April 1st

How can I try new dof foods, hurricane Ian wiped our home out and well, financially we're strapped yet I've spent soo much money out of my savings trying to find Charlie kibble he will eat. He JUST turned two on April 1st, no April Fools he really did, but he will only eat the cats kibble (purina) try to eat their poop (as a certified dog trainer I am trying to break him of this new habbit) but I digress he will not eat anything other then moist food which comes in 6 individual packs BUT I CANT AFFORD OT, I cannot continue letting him eat cat food, and I'm worried because although the vet says he's OK I see him struggling to poop WHEN he does, I give him plenty of water and am trying EVERY brand of dog food (dry) I can't afford to do this anymore and I'm becoming concerned, I'm hoping there is somewhere or some one who can help me w advice of a place known to help w this or may e  a giveaway or test of dog food IM OPEN TO ANYTHING. PLEASE!! Tha k you all Happy Early Mother's day and may you, your loved onea, and your fur babies and/or other critters all be safe, happy, healthy, and blessed. XO love the Armas-Smith family.