I’d probably pay at least $50 to fly on a different plane just not to have my parents worry, and my wife is never setting foot on a MAX
The only problem is that whilst you select the flight you want to go on, there’s nothing preventing the airline you have booked with changing their schedules round and putting a Max on where it was previously A N other type. There’s nothing you can do about it apart from offload yourself, and that’s then going to be expensive.