Trying to police this gets into some super fun gray/censorship areas and can get dicey with so many different countries/rules/opinions/feelings/etc…
suggest trying to keep it simple…
if the book is R18 on amazon/bw/etc… for whatever the reason then tag it as adult (if not already) Then any books tagged adult (regardless of the cover get blurred) unless you turn that option off in your own dashboard/settings.
Then possibly for those that are worried about certain topics give an option in the users dashboard/settings to possibly blur/hide certain tags that may or may not be adult but the user can decide for themselves without trying to navigate a mess of personal feelings.
If a book pops up that isn’t R18 on bw/amazon/etc… but it does have certain tags/topics it shouldn’t necessarily be auto censored for all but the user that doesn’t want to see those options, if flipping on those tags they want to personally blur/hide will kind of kill 2 birds…
Realize of course not everything is tagged necessarily so it won’t be perfect but users could add tags they know are real (sure there could be abuse but overall probably not too big a deal) and anything that isn’t tagged adult could be tagged or request the librarians to update.
some random thoughts… personally books are books
if there is something I’m not interested in I’ll just move on