I got into a discussion about this on the TheGoodPlace subreddit before I left. You've hit the nail on the head there - it's not possible for you to get bored, listless, frustrated, unfulfilled, etc. in a perfect paradise, because then it wouldn't be perfect. If you're imagining those effects, then the paradise you're imagining isn't a perfect one, and so is irrelevant to discussions about a perfect one.

A slightly more interesting discussion is "I, as I am now, dislike the thought of becoming a pleasure-zombie in the future. It makes me uncomfortable now to consider being motivationless and content in the future" - which, sure, fine, ok. Sounds like internalized protestant work ethic to me ("I don't deserve to be happy unless I'm working hard, and I only know that I'm working hard if I'm miserable"), but at least it's not logically irrelevant like the first argument.

The most interesting version is "I don't see a continuous line of consciousness between me and the hypothetical-future-me who lives in bliss, so there's no reason for me to be concerned with their fate - they're not really me" - which is pretty subjective depending on your views of continuity of identity.