Exactly what I did. I had bought a 1+1 year subscription directly since they were giving the second year for free at the time. But the app experience was so bad that I paid separately for the second year to get to through Amazon prime as a channel.
No way...i have 3 TV devices...i don't want it to use under prime account anytime....btw i never faced any issues in TV app and not watching in mobile anytime..using in TV from few years...not a single additional subscription i buy in prime.bcoz afaik it can't be used in any other devices without the same prime account login..