Hi David and welcome to this forum .....
Although my initial tumor was not as large as yours, I can identify with your fears of life after treatment for your AN.
Because of the size of your AN, if I were you I would seek out the most experienced neurosurgeon I could find ..... one with vast experience successfully treating specifically acoustic neuroma, not just any brain tumor. This is one time you want someone who is tops in the field.
Most highly experienced surgeons will discuss the surgical options with their patients before surgery. I, as well, was terrified about having facial nerve damage so I discussed this at length with my surgeons. They assured me they would not try to remove the entire tumor if it was wrapped around the facial nerve, but rather remove what they could and then zap it with radiation later if it began to grow.
Much depends upon the type of tumor you have (sticky vs easier to remove in total) and exactly where it is growing.
If you look at the ANA web site, you can see a place for questions for your physician, among many other resources there. See:
https://www.anausa.org/pretreatment/questions-for-your-physician#questions-for-the-acoustic-neuroma-surgeon This is a good list to make certain you have asked the right questions.
Let us know how you are doing.
Thoughts and prayers.
Clarice