Is it permissible to buy a car from the company I work for by paying a 20% down payment and financing the rest over 6 years with an interest-based loan at 3% interest?

It is not permissible to purchase the car with the aforementioned condition, because it is an interest-based condition that contradicts the intent of Islamic law. A sale that includes this condition is invalid according to the Hanafis, void according to the Shafi'is and Hanbalis, and necessitates the annulment of the contract according to the Malikis. Based on this, it is not permissible to conclude this transaction, and if it is concluded, it is void and must be annulled.