Is selling cars by installment payments, while retaining ownership until the full amount is paid, and insuring them with comprehensive insurance through insurance companies that claim to be cooperative, permissible or impermissible?

It is not permissible to retain ownership of a vehicle that has been actually sold; rather, it is permissible to mortgage it until its price is paid.

If the insurance is commercial, then it is not permissible to engage in it or to assist the buyer with it, due to Allah's saying: ﴿And cooperate in righteousness and piety, but do not cooperate in sin and aggression. And fear Allah; indeed, Allah is severe in penalty﴾ [Al-Ma'idah: 2]. However, if it is compulsory, then it is permissible due to duress.