Option for struvite diet food?

My cat is sensitve for struvite and cystitis. She has been on a special diet (RC High Delution) , after that, her urine was back normal. I started to give her diet food to occur struvite. Later on, she had struvite again.

This happened a few times so the vet assistent told me to give her RC High Delution her whole life.
Since I am not a big fan of giving diet food for a long time (of course, there are exceptions), I'd rather don't do this. I don't think it's good for her health, nor her kidneys particulary. But of course it's not my intention to let her struggle with struvite all the time.

Someone told me about supplements. to sour the urine. ( I hope this is written correctly in English )
He said you can give cats with struvite 'normal' food, just like my other cats. But you can add this supplement called Vétoquinol Care (Or uro-pet, it was first called Uro-pet).

However, I can't find much on the internet about people who do this. When my vet 's back, I will ask her what she thinks.
But I was wondering if anyone has experience with cats and struvite, and giving normal food including a food supplement like Vetoquinol care?

I did a search on the internet for Uro-pet for the ingredients. Methionine racemate (a derivative of Methionine) is a component of Uro-pet. I would also have recommended Methionine (plain without any added ingredients) but you need some guidance about the dose; too much and you can cause the opposite type of stone. I believe other people supplement with Slippery Elm Bark.
The general rule of thumb at least in the USA is to feed cats who are prone to UTIs wet food (avoid fish) and do whatever you can to get your cat to drink more water (like adding water to the wet food, a pet drink fountain). I believe that RC High Delution is dry food; I would ask your vet if it comes in a wet form.
I am not fond of prescription food before everything else has been tried; sometimes the Rx food has stuff in it that isn't really beneficial and a tiny amount of methionine. (Though I know other posters have had success ONLY with Rx food.)
Ritz is prone to stress induced UTIs. I fed prey model raw. Turkey breast has the higest amount of methionine, so I feed her that in her rotation as well as freeze dried turkey breast treats. I also try to keep stress to a minumum: I live a fairly quiet, routine life. I use Feliway plug ins; not sure they are in your country.
Good luck.

Thanks for your reply.

I have about 8 water bowls in my house. Each room has at least one water bowl. Downstairs I have a water fountain. She drinks very well, which is good.

My vet assistent said there is no wet food from RC high Delution, so she gave me Hills C/D. My cat loves food but she doesn't like this hills wet food. I tried raw food as well, also for my other cats, but they don't like it. I tried different brands, mixed it with wet food, but none of my cats ate it.

Yes, there are Feliway plug ins over here. I have Feliway spray, using it when I have to take one of my cats to the vet for example.

She loves her valerian cushions though, and I live a routine life as well There have been some changes lately though, and she got a bit stressed (I adopted a new cat). They seem to like each other now, so that's good.

I think I need to ask my vet about the Uro Pet. Heard that too much methionine is also bad for the kidneys..? I am always very concerned about the kidneys of my cats, since I lost two cats with kidney failure and I've seen more cats with kidney failure.. Unfortunately this is quite common in cats so I don't want to burden the kidneys as far as possible.