yaySIM does not offer an unlimited data eSIM for Germany; all of the plans listed have a fixed data allowance. None of the available packages lists the data cap as unlimited.
The provider offers fixed data plans instead. For instance, the DE_50_30 plan gives 50GB for 30 days, and the DE_50_180 plan also provides 50GB but for 180 days. Another option is the EU‑35_100_180 plan, which supplies 100GB for 180 days and covers Germany plus 34 other countries. Choosing a fixed data plan can be more cost‑effective unless the traveler is an extremely heavy data consumer.