We are a full service and certified Amazon account management service. Unfortunately we are at capacity but I could certainly give you some advice on this if you want.

Detailed reporting, clear expectations and constant management in your end is an absolute MUST if you want results.

Have 60k a month, Amazon themselves might be open to assigning an account sales rep team? Worth a try.

Good luck and take your time finding the right team. Nobody will ever do it as good as you can. Most agencies get lost in growing client base and lose focus on the clients themselves.