I've recently taken a trip into "Weird Fiction", which is scratching my itch for more variety in fantasy.

I'm also finding that just "getting old" means the more books I read, shows I've seen, etc, the more I find myself saying "oh I've seen this kind of thing before". True, non-dopamine-based novelty is harder and harder to come by.

I think they're separate problems, though I'm going to make a huge leap and say that I think the writing problem is actually in part a function of the dopamine problem. Writers are both influenced more by "short media", and required to cater for audiences who enjoy/are addicted to it, even if the product is long-form.