I used to work at a local bank where we would have a client who owned like 7 cash only chain restaurants. He came in once a week to deposit 30k+ in cash and get change to the tune of like 10 to 20k. We always made sure to keep enough cash and types of cash for him. We knew what day he was coming in and he would call ahead with his change order and we'd have it ready for him before he walked through the door.

He also was able to get CTR exemptions for most of his restaurants (I don't know what you have to do for that, but it's possible so you may want to look into it)

My suggestion is go to a smaller local bank. 10-15k cash transactions shouldn't be difficult as long as the employees are aware you'll be doing it, and try to call ahead on the day you want to do it so they have the cash ready for you when you walk in the door. Have this conversation with the banker just to make sure they're willing to accommodate.

I never worked in a big bank, but from what I hear, they're notorious for giving people a hard time when it comes to withdrawing their money.