I think given how high your ejection rate is that you are right to be cautious and explore your options. Are there any cures out there? Probably not. Eventually it will have to come out.
Five years ago I had a HIDA scan and an ejection rate of 23%. Since then I have been on a steady regimen of Ursodiol/actigall which can dissolve gallstones. I have been pain free 95% of the time. The downside--it is rather expensive so you need good insurance.
If you search the internet there are alternatives remedies. From what I have read the olive oil and lemon juice treatment is rather worthless. However, there are suggestions that things like lecithin, apples/malic acid, and cholesterol lowering medications may be helpful. There is one commercial product aimed specifically at this problem (we cannot name them on this board) that contains
inene, camphene, cineol, menthone , menthol, borneol, and olive oil. Again I am unclear how effective any of these are. It would seem that one goal is to lower the amount of cholesterol in the gallbladder so that it mixes with the bile instead of precipitating out and forming stones.
Nexium and PPI's may present a problem. I used them initially and got some relief. However, there was a small study done several years ago that claims that they will slow down the contractions of the gallbladder.
Titchou is right as always about the risk, however you are in better shape than those who come on here with a 5% ejection rate and need their gallbladder removed now.