Assalamualaikum wa rahmatullah dear Ustadh, Is it a bid'ah to make the same dua in sujood every witr (mother tounge) since I ask for specific stuff. Jazakallah kheir

No, it is not a bid'a. It is from insisting in your du'a. You should also always diversify. It doesn't have to be every single time; it is favored that you diversify, so at certain prayers, ask for something else. Barakallahu feek so not every single time the same du'a.