Being a cop in Germany is much easier and less risky job than in US, because they have 50% more cops per capita while having something like 15% the crime rate of US. This means that, as a very rough estimate, there is something like 16 times more crimes per cop in US than in Germany. This is made even worse by things like US criminal being much more insane and erratic than German ones (Germany has a more collectivist, order-oriented culture, and will institutionalize miscreants much faster and for much less serious offenses than US will), and case overload forcing US cops to focus on the worst cases and worst offenders first.
For this reason, more people in Germany will put up with strict credential requirements and low pay than in US. To make police force more professional in the US, we first need to stop most crime, and for that, we need to hire a lot of police (to bring the crimes-per-cop ratio closer to low crime countries), and massively increase incarceration of repeat offenders, who are responsible for the bulk of the crime. It will be extremely hard to both hire more police and also to make standards higher: you’ll end up with highly professional cops who are too busy to help you unless you’re being actively murdered.
For this reason, more people in Germany will put up with strict credential requirements and low pay than in US. To make police force more professional in the US, we first need to stop most crime, and for that, we need to hire a lot of police (to bring the crimes-per-cop ratio closer to low crime countries), and massively increase incarceration of repeat offenders, who are responsible for the bulk of the crime. It will be extremely hard to both hire more police and also to make standards higher: you’ll end up with highly professional cops who are too busy to help you unless you’re being actively murdered.