This really comes down to the shape of a room, the seating/position of the ‘sweet spot’ and how things sound best to yourself when seated in the usual/regular listening location.
I personally like an (ideal) stereo wide soundstage, with two speakers, playing separate channels, out in front and on either side of where I regularly sit for music playback, rather than two separate grouped speakers playing in mono, but if that can’t be achieved perhaps due to location of furniture, shape of room etc; then in some instances leaving the speakers ‘unpaired’ but ‘grouped’ can sound better.
The answer is to try the speakers for a while as ‘standalone (mono), but grouped together’ ...and also as a ‘stereo pair’ and see which suits your room layout and (more importantly) which setup sounds best to yourself where you regularly sit ...and then just go with that.