Unfortunately, probiotics have not really proven to be effective in preventing vaginosis
In addition, the bacterial flora can be very different from one person to another in terms of the strains and quantities present, a bit like a fingerprint... Commercial products are not customized to be really useful..
You will need to focus on non-pharmacological measures, such as:
Avoid using soaps to clean your private parts, except for a product without perfume or agent that could be irritating, like the Dove bar
Avoid tight-fitting clothing
For hygiene after a bowel movement, wipe from top to bottom (front to back)
It is recommended to urinate (if possible!) after sex.
I hope this has been helpful to you, and if you have any other questions, please don't hesitate to ask!