Curious, I never want to fly in one of these. How can one achieve that in a realistic way? Let's say airline changes plane after I booked, then I wouldnt get a refund. Is there a solution to this?
You will never be able to get a refund for plane changes. Even airlines with no MAX aircraft of their own could operate your flight with a MAX if they use code share or wet lease.
So while you can make your risk small, you can never be sure, without accepting that you may need to turn back at the gate. But on the other hand I assume you'll be OK with flying it once it has flown for a number of million miles in a few years from now. After all, the airlines that operate non-MAX 737's for the equivalent flights will be flying older and older craft.
The best plan would be to avoid airlines that own the plane, but that will be impractical for most. Even then you might be re-routed onto another airline or third party plane.