Unfortunately I don't have enough space on either wall as the area
next to the TV is all glass shelving and glass doors floor to ceiling.
Beyond that the distance from the TV is too great.

What about using two surround sound speakers side by side under the
TV. Two of these would fit to give me stereo sound instead of mono
from the center channel. Would this be better?

Another option is ceiling installed speakers. I could go that route
and keep the center channel under the TV. I see that Klipsch has
ceiling speakers with directional tweeters (no idea how well this
would work).