Question about deductible and copay

We have a surgery coming.up and we don’t have exact costs, but last time it was roughly $8,000 before insurance. Our deductible is $1,300 and OOPM is $3,000. After deductible the copay is 20%. It’s been a long time since the last surgery, and last time we had to fight for weeks to even get insurance to cover anything. (It’s ear surgery for my girlfriend who is going deaf. They always say it’s not medically necessary, but at the same time say that a hearing aid is not a viable alternative. They being the insurance company, not the doctor. Apparently the doctor gets no real say over what is necessary.)

My question is, if all gets approved will the surgery cost $1,300 total, or will we have to pay the copay of 20% on the remainder of the surgery bill? I understand there will be separate bills that we will have to copay. Meds, anesthesia, and stay, are all separate and we will have to pay the 20% copay. But for the actual surgery itself, if it came to $8,000 would we pay the $1,300 deductible ONLY, or would we also have to pay $1,340 on top of that as 20% of the remainder of the $6,700 after deductible is taken out.

My girlfriend is so on the fence about surgery because she doesn’t want to get stuck with a crippling bill and have to fight for weeks to get them to cover anything at all. They would not pre-approve, or give any indication of whether they deemed it medically necessary ahead of surgery, so we won’t know if they are going to fight it until afterwards. It is definitely medically necessary. It is not just a surgery to restore hearing, it is to prevent a brain infection that is very likely to occur if surgery is not performed. Her ear canal is almost entirely closed and there is fluid build up that cannot drain. It is painful, she cannot hear at all out of that ear, the other ear is iffy, she has very poor balance right now, and untreated it could be life threatening.

They wanted to perform the surgery ASAP, but we already put it off until January of next year because of insurance. We know it’s one surgery and the doctor warned there is a very real likelihood there will need to be a follow up surgery a few months later. We want to reach out OOPM so that the next one won’t be as scary. I know that once we hit $3,000 for her for the year they said we aren’t responsible for paying any more.

I wish it was easier to understand insurance. I wish the company would help explain. I wish the doctors didn’t double bill. We already got 3 bills for one hearing appointment that insurance didn’t cover at all. Paid the first, asked why there was a second, they said one was for the hearing test and one was for meeting the doctor afterwards to talk about the hearing test. That’s fine, I guess. Got the third bill and they said that it was for the same hearing test. Asked why we got 3 and they couldn’t answer. Said we had to pay it or they wouldn’t continue to see her. Another doctor is not an option. It’s a specialized procedure and the next closest doctor that can do it is out of network. We would have to travel 600 miles to see someone in network, with multiple appointments required, she would need transport back afterwards, and we have kids.

Thank you for any replies. I really do appreciate it. Sorry for the wall of text, just wanted to give as much context as I could in case someone was going to suggest an alternative. Sorry if I worded anything weird, and sorry for not understanding all of this. We just want to be prepared.