My favorite probiotic for cats is Felix’s Flora designed specifically for cats. Also, find a quality food and stick to it. Cats cannot handle a lot of change when it comes to food. Try sprinkling on some freeze dried topper to make food more appetizing for her. Also, bring kitty to vet to make sure. It’s not something else going on. Hard to diagnose from here.

pure pumpkin and yes stool testing at vet

This is a vet visit situation--most likely it's parasites or a bacterial infection. Giardia, for example is notorious for causing stinky gas. Get a fecal analysis. If it's both parasites and bacteria, it's a three-stage solution: a broad spectrum dewormer, a liquid antibiotic you can mix with food and a probiotic powder to restore gut balance. We've been through this with feral rescues many times. It's possible it's a more serious digestive issue, but in our experience that's rare.

Please take her to the Vet it soubds like Giardia and she’ll need meds

I have a cat that is allergic to chicken. She’s now on a diet with no chicken products and she’s so much less stinky.

Take her to the vet. A nutritionist vet preferably. He might suggest you to feed her with médical food such as Hill's I/d digestive care but it has to be under vet's control. You should do something not only for you but for her : such gas might be the symptoma of sth wrong

I would cut dry kibble if you can or limit it. It has a lot of carbs and dry food is known to cause urinary issues and kidney disease. Raw food is good although a lot of vets don’t recommend it. They like to recommend whatever they’re selling because of commissions.

I had a stray like that with awful foul pops and gas. Finally needed some antibiotics to clear up an occult infection of stool. Street cats eat out of the garbage and pick up a lot of parasites.

Deworm?

Trip to the vet for blood work and ultrasound