On the same 65.000 € gross, a worker takes home roughly 15 432 Kč more per year in Czech Republic than in Germany. That gap reflects the tax structure alone — before rent, healthcare, or savings behaviour come into play.
Housing is the first multiplier. Czech Republic has moderate rent pressure, while Germany has moderate rent pressure. The two markets behave similarly, so most of the gross-to-net advantage flows straight into disposable income.
Healthcare and pensions go in the opposite direction. Czech Republic runs a public healthcare model — Statutory health insurance covers essentially all care. Germany uses a public model — Statutory health insurance (~14.6% split with employer) gives full coverage. The country with lower take-home often shifts costs that the other country leaves to your private budget.
Net-of-everything, a relocation decision should weigh strong public welfare in Czech Republic against comprehensive welfare state in Germany, plus differences in pension capture, social safety nets, and city-level cost of living.