Is it considered usury or bribery if shares are acquired from a bank through a person who takes a commission from employees from the same financing amount after it is deposited into the bank account?

It is permissible to engage in Tawarruq (monetization) using shares under certain conditions: that the shares are sharia-compliant (naqiyah), owned by the bank, and transferred to your portfolio before you sell them. Also, the bank must not impose a penalty for late installment payments. As for taking a commission for assisting you in obtaining financing, if the person is not a bank employee and helped you, there is no harm in taking a commission as a jua'lah (fee for a service). However, if the person is a bank employee, what he takes is considered a bribe, and gifts to employees are forbidden, as the Prophet, peace and blessings be upon him, said: "Gifts to employees are ghulul (ill-gotten gains/embezzlement)." If the financing is in his name and he will give you the money and take a commission, this is not permissible because it constitutes Riba (usury/interest).