You would need to fully remove the ceiling can fixture from the space, run speaker wiring to those locations from your Atmos enabled surround receiver and remove the 120v from those locations. If your TV is in the corner, instead of the center of the room, you will also be putting the speakers in the wrong location.
I'm a big fan of having a lot of lighting in a room, so I would leave the lights in place and just put a dimmer in so that the lights could be lowered to a level that makes you happy and if I wanted to add speakers, I would ensure they are in the proper location for where the TV is in relation to the viewers. Generally, when I see TVs in corners, I end up seeing pretty poorly setup surround systems. Speakers are rarely properly located.
Put the lights back, put a dimmer in, don't install more speakers into the wrong location.