Pros and Cons of Exhaust Dumping After the Axle

I asked this question on another forum but did not get any responses, so I’ll try here:

I am thinking about replacing my muffler but keeping the resonator and having the exhaust exit after the axle. I only want an exhaust tip to direct gases away from the truck. For clearance and appearance, I prefer not to have exhaust tips out the back or sides.

So, with a 45-degree turn-down (down and away on the passenger side) after the axle, what are the real risks of corrosion or CO buildup at idle? I hope the 45-degree angle will reduce drones, but my main concern is safety. If I idle for an hour, is there a risk of CO buildup? I rarely do this, but I like to be prepared for the worst-case scenario. I have considered installing a CO monitor just in case.

Thanks for any advice.