IF you keep your speakers in the corners (rather than moving them out when listening):
I would not start with a sub or subs, until after I played them for a while so the cones are loosened up, then measure with an SPL, then consider sub(s).
IF subs, I favor a pair of stereo subs, front firing, no ports, (or if ports, front firing) adjacent to the mains, so that the bass overtones which become directional give you the added imaging of bass, i.e. jazz bass player is ....
Sooo, if you really think you will need/want subs, you do need to anticipate their placement as you mentioned above.
btw, I’m 77, I diddled around with ’more bass’ in my youth, I think ’enough bass’ is smarter and as enjoyable. I favor mains with large woofers, done.

