Yes, they have the same meaning which is "very", "so","much", and "a lot". I mean they express the intensity and the large quantity. كثيرا = a lot. اقرأ الكتب كثيرا(Akrao alkotoba katiran) = I read books a lot. => اوى is more used in Egyptian dialect. "اوى" = "جدا " = very, so. We can use them with the same way. انا بحبك اوى(Ana bhebek awi) or انا بحبك جدا ((Ana bhebek jidan ) = I love you so much. أنا سعيدة اوى(Ana sayida awi) or أنا سعيدة جدا (Ana sayida jidan )= I am very happy. I hope these examples help you.

This is a very smart, specific question, dear Inna. Let me first add some examples. أكلت كثير / نمت كثير / لعبت كثير / سافرت كتير تعبان جدا - قوي / الأكل حلو قوي - جدا / المحل ده غالي جدا - قوي / الجو جميل جدا - قوي So we can translate جدا as "seriously" and قوي as "strongly" and you can use both to emphasize an adjective. While كتير means "many times" or "a lot" and you can use it to explain the frequency of an action. So we use it usually with verbs.

اوي وجدا ليهم نفس المعنى يعني ممكن تقولي كتير اوي او كتير جدا غالي اوي او غالي جدا جميل اوي او جميل جدا