So why among the options of "very much" it shows nagyon szépen, but the sentence Köszönöm nagyon szépen, viszlát is wrong?
That's not natural word order. The correct phrase is "nagyon szépen köszönöm". (Interestingly, if you only use "szépen", you can't put it in front of "köszönöm").
Oh, I see, Master Yoda style... (then, total madness). Very much thank you
The translation is incorrect. Should be 'Nagyon szépen köszönöm, szia', but is not accepting