I’m … not touching your second point, but on the first: it’s even worse than that. “In for a penny, in for a pound”.

Why would anyone who committed a murder surrender if they know they’re going to die anyway? Especially when dying in a shootout looks better than “botched execution”. How many of these crimes are already committed by someone that only cares about themselves and hates the people around them? What’s their incentive to stop?

The death penalty seems to me like a great way to turn a murder into something worse.