Hi all,
Noob to the forum, and really hope s'one can give me a suggestion on how to clean my stained stone tilled bathroom and shower floor

I've tried all regular cleaning products, including bleach and even a BBQ cleaning spray!

(Incase it was greasy!)
The tiles are a semi rough surface, I chose them for the bathroom as I didn't want anything slippery, they've always been regulary cleaned but over 5 yrs have stained badly (see pics)
Bathroom Floor
Shower Floor

The shower flooring is the worst and the rest of the floor is just 'grubby'.
The pics were taken after I had just tried a 'Baking Soda, Salt and Vinegar' mixture on the shower tiles, obviously with no joy
Brand Name product suggestions won't be of use to me as I live in Thailand and they likely won't be available, but there are home depo type stores where I can get general stuff.
What can I use??!