A few things i found while searching on the subject. also as background i do phone costumer service 35 hours a week asnd have been dpoing so for years. Only very recently did i resolve my voice issue completely and without surgery.
1)dr belanger when i assked for the voice surgery plainly said their failure rate is very high and refused to do it without a 1 year trasining schedule with a voice specialist.
2) succesful surgeries often involve cutting your vocal cords and reattaching them. Scares me to death.
3) proper training alone can give tou a perfecly female range voice. I did it, thouhg i put 15 yeasrs of work into it.
I read 1 article that gave me the answer. It was in french so linking it would not be useful. Will try to give a quick version someday if needed

. But it solved my 1 issue. My voice can go from very low to very high and i did not know what was causing it. Learning which muscle wass responsible fixed it. I got not 1 sir sunce then.
Update : I recorded my voice and it measures btw 175 and 235 hz quite happy actually