Will an employee in a mixed-gender company's appointments department, who carries out recruitment tasks and distributes employees to departments not free of mixing and privacy, be sinful, even though his salary is permissible?

It is forbidden to employ unveiled women or those who do not adhere to Islamic regulations in a mixed-gender work environment. Therefore, you are not permitted to work in this company if your work there will aid in something forbidden or directly involve it. If you still have doubts, consult trustworthy scholars.