My solution was to give up and DIY. I wouldn't dare attempt anything more complicated but a bookcase is among the simplest projects to take on.

The plan B which we used for some things in the house was a custom build. (Not meaning to shill or anything but they did a fantastic job and in your shoes I would explore their bookcases: https://www.dutchcrafters.com/Amish-Bookcases/cat/146). The prices are up there but I figure are about the same inflation-adjusted as what my grandpa would have paid 80 years ago.