Does a young person aged 16 to 21 need a guardian's approval to open a bank account?

No. According to the recent financial inclusion decisions, any young person who has reached the age of 16 and holds a valid national ID card has the right to go to any bank on their own and open a youth account or an independent financial inclusion account and manage it fully (withdrawal, deposit, transfer) without the need for guardianship or the father's signature.