That's ... a bit shortening reality. They are not required to follow precedents from the same level of courts (lower, upper, state court, federal/supreme court), but in practice they do so, particularly if there have been multiple similar cases. Federal and supreme court rulings are effectively binding for lower courts.

Notable disagreements exist as well, for example the Landgericht Berlin who routinely ignores even Supreme Court judgements [1], or the Landgericht Hamburg which is infamous for happily providing c&d orders to a degree other Landgerichte do not [2].

[1] https://www.lto.de/recht/nachrichten/n/lg-berlin-geruegt-von...

[2] https://www.lawblog.de/archives/2016/05/18/das-hamburger-mon...