Speakers for small room

Hi folks,

I'm a two channel stereo guy trying to help out a friend with his HT set up.              He is looking for front left, right and center channel speakers. Action movies (Marvel, James Bond, etc.) are the primary use case.

Requirement is they need to be flat and hang on the wall.

Budget is $2500 - $3000. Used is an option.

Receiver: Denon AVR-987 https://www.hifiengine.com/manual_library/denon/avr-987.shtml

TV: LG OLED C1: https://www.lg.com/us/tvs/lg-oled77c1pub-oled-4k-tv

Subwoofer is a JBL 12" 

He also has two smaller 6" or 8" subwoofers from Cambridge Sound Works circa 1996

Basement room is 11.5 ft wide.  When sitting on the sofa - ears are about 17" from the 'rear' wall.  About 10 ft from the front wall with TV and speakers.

Room is 19 ft Long.  Couch is the middle 11ft of this long wall.  So ears will be between 4ft - 15ft from each side wall.

Ceiling height is 6' 11"  (low ceiling)

Thanks everyone!