"will work" is future simple.
"will be working" is future continuous.
Generally, when we use future simple, we mean we will complete the action. "I'll paint the house later today" means you will finish it. If you say "I'll be painting the house later today", you might also do it tomorrow, and the day after....
However, "work" is an on-going activity, not an action that finishes. That's why with the particular verb 'work', there's no logical difference between the two.