If I switch zones at the mission table halfway through a zone must i redo the quests when i return?

In expacs like Legion and BFA, when we choose which campaign to do first, the different zones on the mission table, let’s say if i leave a zone campaign halfway to do another zone campaign, when i return to the first zone must I redo the quests I’ve done before leaving?

No, you don’t lose any progress, and any campaign quests you have will remain in your quest log unless you abandon them. If you think you will come back and finish the campaign at some point, I would hang on to them so you know where to resume later.

thank you my friend