I'm assuming the rear speakers are above the window. If so, inwalls can work. Aim-able tweeters will be useful.
Could consider moving the sofa another foot away from the back wall (and the side surrounds, too). That will get some needed distance from the rear speakers. It will also help the front L/R soundstage and the TV will look a little bigger.
Deadwood Atmos theater
AV7702 Atmos 7.4.4, SSP-800 PLIIx 7.4
Aerial Acoustics 7B/CC3B fronts, B&W CWM8180 surrounds, Tannoy Di6 DC heights, Hsu ULS-15 subs