3 year opt out. Pay him what he wants and worry about paying him in 3 years, hopefully in the middle of a competitive window
This is the thing, we have no idea who the high earner will be in 3 years, or 5 years. Paying him 45 million a year for 5 years sounds incredible, but he knows in the 3-5 year time frame, the highest earner could be making more than that and he will want to be able to match or exceed it. If you don't give him that opportunity, he will probably go to a team that will.