How can one atone for the aforementioned sins, and will God forgive them and not take revenge on the doer, and what is the way to remain steadfast and abandon them?

It is not permissible for a woman to work in a place where she is exposed to khalwa (private seclusion) with men, as this is forbidden by scholarly consensus. This work must be abandoned immediately, and she should seek employment that does not involve khalwa or impermissible mixing. This can be justified to the family by explaining your exposure to khalwa. It is not permissible to obey one's parents in continuing this work. Repentance involves abandoning the sin, regretting it, and resolving not to return to it. It is advisable to learn about religious matters and choose righteous companionship. Swearing by the Prophet, peace be upon him, is not permissible.