The many options that have appeared for streaming of "premium" content and networks certainly have complicated the Roku menus for Amazon. Would be nice if they had a "no add ons" option to keep the menus simpler as they were pre-update. Lately it seems every "service" with "updates" assumes we ALL want them. For me, it's just more to navigate finding my usual stuff on the screen. They intermix the new premium subs and options with the usual prime and "standard purchase" which, for them, is a good "carrot dangler" but for anyone not interested, a real turn-off.
We live in the interruption-based economy. Every time the consumer is annoyed, someone's making money Seriously though they should at least offer some options. You might try first clicking on the "Prime video" menu option (if still available) because that let you filter to only stuff included with Prime.