In case some of the jobs are a bit abstract I'll elaborate more on your position...

Chef - Quite simple, you are responsible for the meals of ten to fifteen gods.

Butler - In this instance the "supreme being" can be whoever you want, but you serve them 24/7.

Keeper - As the keeper you hold omniversal knowledge and are responsible for certain texts that exist.

Policer - This job is military, police, firefighter etc., all wrapped into one. You're even a politician of sorts.

Gardener - As the cosmic gardener you create new life and species everywhere. You can also let certain species die out.

If you have selected a job and begin to slack off you'll become a slacker with minor powers compared to what you had.

Know everything with an near infinite library? Sign me up

By “whoever you want” do you mean it doesn’t have to be god? Like can I just choose a random person?

Gardening is my passion in life !

By whoever I meant likeness, as in what they look like or where they came from (I.e. fiction, your imagination, etc.) @Radmushroom

So theoretically I could choose a mortal to be a butler to and then after they die I’m free?

You realize you're the butler in this situation right...