Not fulfilling the working hours requirement for a job

Assalamu alaikum,

I work a 9-5pm job in IT for a large company. We all work remotely, i.e. from home. Sometimes I start work late, finish early or take breaks outside my lunch hours. I try make up missed hours by working overtime but often this is hard and I don’t manage to make them up. I have a following questions:

  • Do I need to estimates the hours missed and return my wages back to the company?

  • If I speak to my manager about this and he says it is fine as long as I complete the work, can I keep my wages?

  • Given it is a large company, I am not sure if it is possible to return money back to them. Would it be permissible to give away the money in charity?

Jazaak Allahu khayra,