Your situation brings back memories of having gone through similar problems caused from over prescribing of antibiotics to our late Missy. The information that you have received from this web site took me several years to accumulate.
Hopefully this is going to work for your kitty.
I think you have received some good advice from Rustycat and Hazel.
Just a couple of things that i think might be of help. One is down the line to start introducing kitty to 5 to 10 gms of raw meat as a treat or mixed in the meal, to help get more into species specific food. This will help the gut.
Maybe somewhere down the line you might contemplate getting her onto a species appropriate diet.
Something I found out years ago, that I wish I had followed up on, was Fecal Transplant. I had 2 customers about 5 years apart in 2 different communities who had pups with Parvo Virus. They were Indigenous ladies who were very devastated by the issue and the cost of vet fees. They went this route on their own and had fantastic success and within 24 to 48 hours the issue was all cleared up. I'm not recommending doing this on your own, but I am thinking I would be passing it by your vet if she's open minded.
I'm enclosing a couple of web sites to have a look at so you can draw your own conclusion. Had I done the research when I found out about the Fecal Transplants, it could have been an altogether better outlook for Missy.
https://healthypets.mercola.com/site..._rid=481965611
https://www.animalbiome.com/
If things are not working out the way you're wanting, maybe this would be another area to contemplate