Is it permissible to open a mixed steam bath (hammam bukhari) for men and women at different times as a source of livelihood, and does the customers' failure to adhere to Islamic manners affect the permissibility of the project?

It is permissible to open bathhouses and work in them, provided that Islamic regulations are observed, such as not uncovering 'awrah (private parts) and preventing the mixing of men and women. If the work involves violations of Islamic law and these cannot be controlled, then it is not permissible, as it falls under cooperation in sin and aggression.