I still want 3 way, enough bass so I don’t feel the need to add a sub, my conclusion: not gonna get that from a 6-1/2" driver, so 8" or 10"?
I chose to refurb AR-2ax, with a 10" woofer: my 1st decent speakers in the late 60’s while in college. They are the biggest bookcase speaker I ever owned, designed with 11-1/2" depth, to fit
in a bookshelf
on a bookcase
on a stand, angled up to aim the tweeter at seated ear height. I have them at seated ear height in my office, imaging dead center of my monitor, what a difference compared to all the prior compromises I made in my office.
https://www.hifishark.com/search?q=ar-2ax

no port, separate level controls to adjust the mid to the woofer, and adjust the tweeter to the mid while listening, in any space.
I have not heard them, but they are currently selling the KLH-5, 3 way, no port, 3 position level control, but they are too deep to fit IN a bookcase
https://www.crutchfield.com/p_700M5NNB/KLH-Model-Five-Nordic-Noir.html

I just glanced at all the bookcase speakers The Music Room has for sale, nothing I want, and some of the prices are scary.