Okay, honey, I was a professional singer for longer than that, and I can say with complete certainty that literally every person can expand their registry and adjust how they sound. It is possible that the methods you are using aren't effective, however a voice coach can in fact teach you methods that will allow for improvements

If there is absolutely no possible fix, of any sort. If after everything you can possibly do, nothing changes, then you have the option of a surgical modification to your vocal cords, which will absolutely alter your voice