You live in Germany, you actually have the luxury to not work. Everyone gets a roof, food and healthcare, even without working.
Also, this is not an argument against your co-workers: if they do less than you, isn’t your job safe then and everything is good?
I don’t want to work with people with this mindset.
Then you should stop working, because they will be everywhere to some degree.
Are you advising me to ignore patients when they call?
If your work is done, that’s exactly what you do. Or if you’re in the process of doing something else/handling another patient, idk how it works exactly. It’s the responsibility of management to ensure that all patients get treated, not yours. You can and should of course report when this doesn’t happen and you notice it.