A gynaecologist friend of mine told me a long time back that the tightness of a woman, or lack of, is usually just down to how we are made. I am past middle age and have given birth in my twenties. Despite doing this work full time for many years I don't think I am much less tight down there than when in my 30's. For that I feel fortunate.
Having read comments that a sex worker must be as slack as, select stupid words, we've heard them all, it just shows the ignorance of many men. A young lady I worked with when I first started was 19 yes old with no children and I was very surprised at how loose she was ( how did I know for sure? use your imagination 😱 ) and she commented on this herself.
I have no answers how to remedy the problem but suppose trying various options mentioned are always worth a go if it bothers a woman so much.