"უნდა იცოდეთ" could be უნდაა (but "იცოდეთ" is imperative, so maybe შეიცოდეთ? But these might not be correct forms. Alternatively, maybe "იცნოთ", "გონებულობდეთ", "შეიგონეთ". Not sure. Alternatively, use verbs of similar meaning like "შეძლებდეთ", "მოხმაროთ", "ხელახლობოთ". Still not sure.
Moving to the next sentence: "ნიგაბი 2 ქართულად არის ერთ-ერთი ყველაზე პოპულა nigabi 2 qartulad
"თქვენ" can be "თქვენი" (your), "თქვენთვის" (for you), "თქვენით" (by you). Wait, maybe "თქვენით" is not correct. Let me think again. Maybe "თქვენით" is a prepositional form, but perhaps "თქვენით" isn't common. Maybe better options like "თქვენი" (your), "თქვენთვის" (for you), but the user asked for 3 alternatives. Hmm, perhaps "თქვენი", "თქვენთვის", "თქვენთან" (with you). Not sure if that's valid. Maybe better to check a thesaurus for "თქვენ". "შეიგონეთ". Not sure. Alternatively