If you purchase a plane ticket for a flight that appears to be carried by a bombardier model, would you refuse to board the plane at the gate if the bombardier plane ended up requiring maintenance and they swapped it out for a 737?

How many vacation days would you sacrifice out of your week in Cancun to stand by that belief?

The 737s are the most common airliner in the world, more than 10000 have been built, and more than 1000 are in the air right now. The pre-MAX 737s are just fine (though it had some issues with the rudder in the 90s, and, well, nearly 2% of all 737s built have been lost (184 hull losses) with nearly 5000 fatalities. Goes to show how much they fly.)

You have already, probably multiple times. The 737 model is proven over 50 years of service.

The Max has issues, for sure, and I will be weary of that as well as the upcoming 777X, but I wouldn't hesitate to get on any prior 737 or other Boeing model.