Is it biblical to take a vacation from work?
Employment is governed by rules set by governments and the agreement between the employer and the employee.
For example, under the Law of Moses, the Israelites were required to not work on Saturdays (Deuteronomy 5:12-15). They also had special religious holidays off, known as holy convocations (Leviticus 23). These were government-directed holidays for everyone. Nothing is stated that would forbid an employer from giving additional time off.
We find Jesus working hard while he was on earth. There were several occasions when he went off by himself (eg. Matthew 4:1-2; John 6:15). He also had the disciples take breaks (Mark 6:31).
If your employer offers, as a part of your job, two days off every week, holidays off, and three weeks of time to use as you wish, that is the package you received. There is nothing morally wrong with taking breaks from your work that your employer has offered you.