I prefer to do various tasks rather than to do one task. Here are some reasons to support the idea.
First of all, I can improve practical job skills by doing various tasks at a time, even though I would feel a lot of pressure about it.
Secondly, realistically, in the office there are full of work (The subject of "be full" should always be something that can be filled, as in "my schedule is full of work." In your paragraph, it might be better to use "there is a lot of work") to do at the same time, employees need to get used to doing many tasks. In order to gain recognition at work and get a promotion easily, an employee has to do various tasks at a time.