Thanks all for the answers! Small update on the costs: I managed to get 0.05 EUR kWh electricity costs from a nearby company. But still, I guess ETH is not worth it to mine, but what about BTC? If I buy antminer S19 pro, which are still available for about 8-10k EUR, I could make a decent profit as passive income per year at such low kWh costs. What do you think?