It already worked fine during the first lockdown last year. At the end we were down to numbers at which tracing contacts and quarantining them worked quite fine for a while. This would have been an acceptable level where people would have been able to do quite a lot of things but not everything. A lot of people overdid it though. Parties, weddings, ... if nothing had ever happened. Unfortunately the response was slow and weak. Now we still deal with the consequences.
You might advocate for Germany closing its borders earlier and for longer, and forcing police registration of fellow Europeans, but personally I think that is horrible. I see restrictions on free movement in Schengen and challenges to European integration as much more of a problem in the long term than COVID morbidity.
