Is it permissible to levy a financial penalty on the buyer in the event of their delay in paying car installments, knowing that the sale is conducted through Islamic-compliant installments and does not include interest?

This increase, in exchange for delaying debt repayment, is usury itself. Allah Almighty has commanded to give the one in hardship a delay without any increase, as He says: (And if there is one in [financial] hardship, then [let there be] postponement until [a time of] ease. But if you give [from your right as] charity, it is better for you, if you only know.)