Soft magnetic materials play a crucial role in determining the efficient operation of power electronics and electrical machines. Their magnetic properties strongly depend on the microstructure. However, the relationship between the microstructure, local magnetic domain structures and their impact on magnetic properties remains elusive. This correlation is crucial for understanding the fundamental magnetic behavior of soft magnetic materials. In this work, we investigated Fe-Co-Ti-Ge alloys by introducing tunable ferromagnetic Heusler type phases into a ferromagnetic matrix. The microstructures were characterized using techniques ranging from macro- to atomic-scale, particularly with (scanning) transmission electron microscopy ((S)TEM). Magnetic domain microstructures were investigated with Lorentz TEM and differential phase contrast (DPC) – STEM. The magnetic properties of these alloys show a good combination of high electrical resistivity (202 - 252 µΩ‧cm), high Curie temperature (˃ 1000 K) and moderate magnetization saturation (0.69 – 0.92 T) and coercivity (390 – 1099 A/m), but also in a broad range with different microstructures. The correlation between the microstructure, evolution of magnetic domains and the bulk magnetic properties will be discussed. These results indicate that the physical properties of Fe-Co-Ti-Ge alloys can be tailored by microstructure tuning.