Wet food for yeast and environmental allergies

[Jude19]

I wonder whether anyone can recommend a wet food, tinned or pouches that would help my 9 year old boy with his itchiness and yeasty ears. He has itched from 12 weeks old, has no sores or inflammation and has been on Apoquel for most of his life.I am happy to keep him on the apoquel and also to return to his immunotherapy jabs I was giving him monthly but wonder whether a change of diet might help and prevent the need for Apoquel. His current diet is Scrumbles, grain free salmon wet and Wellness cold pressed ocean fish kibble grain free, but I have been reading that the grain free might possibly cause a heart condition and as he has been on this diet for some time would consider a change. There is so much info online and I realize that kibble carbs are bad for yeast but don't mind mixing the 2 if I can find anything better. He will eat anything so no worries there.

[Joules]

Watson is on Arden Grange white fish and potato sensitive - wet and dry food. It has helped his itchiness a lot (he is also a yeasty boy) but not totally erradicated it. Tried lots of different things - apoquel worked, but not good to be on long term. It's so frustrating!