What is a recommended mileage to ghange the cam chain?
Normally it’s a life-of-the-engine thing, no recommended replacement interval, as long as you’re sure it’s a chain and not a belt.
When it gets noisy. More often than not they outlive the life of overall vehicle.
Your roller type cam chain, if that is what you have will last longer if you drive moderately. Running your engine repeatedly up to redline will reduce roller cam chain life. I have done it both ways and that is what resulted for me.