Economical alternatives to Royal Canin Gastrointestinal Low Fat wet food

So I just got my dog out of a scary bout with gastroenteritis (depressed, lost appetite, 105 fever, black tarrry stool). No idea what she ate or if just bacterial infection caused - she has a 1 acre wooded yard.

After seeming nearly gone, she is well again, happy & hungry and energetic. Counting my blessings!! I decided to keep her on the food the vet gave us to recover on (along with antibiotics, probiotics, etc, etc). I just ordered a case of it - Royal Canin Gastro Low Fat - only to get major sticker shock - $99/case!

Okay so that may not be doable long term. I googled alternatives to Royal Canin, and am dizzy from so many hits, I don’t know who to believe.

I don’t want to rock to boat with this dog, having just brought her back from the brink, so I’ll keep her on the pricy stuff awhile. But surely someone else has been through this - did you manage to find something quality and dependable for a sensitive stomach, gastritis prone dog? I’m reading that the condition can recur in some dogs, so trying to be preventive. She is a 135 lb Caucasian Ovcharka, 5.5 yrs for the record.

So turning yet again to the COTH collective - please does anyone know any cheaper alternatives to Royal Canin that have stood the test of time in your experience?