That is really very tight. €50 savings per year is not much. As soon as one of the prices changes, it most likely won’t be worth it anymore.
Generally, your household electricity seems relatively expensive to me. We change the electricity provider once a year, as long as there are cheaper offers, and so we always have the lowest price. Currently 25.37 cents. That is cheaper than your heat pump tariff.
Is the 5,000 kWh annual consumption correct for you? We are at nearly 7,000 kWh with the same house size and 2 people. But we also have quite a bit of technology and already had 3,000 kWh consumption in our old rental apartment. The heat pump consumes about 3,500 kWh per year for us. 5,000 kWh still seems quite low to me for an entire detached house.