Yes, Gears of War 4 supports surround sound on Windows 10.
Yes, Gears of War 4 supports surround sound on Windows 10.
Check the PC settings for the relevant configuration; if not found, your settings might be misconfigured.
It looks like your main device is set as a surround setup, but you need to determine the right bitrate for your system. On my machine it was 24 bits at 44.1kHz. Some games handle this automatically, while others may have problems—like mapping 5.1 channels when 7.1 is chosen instead. Recently tested games have worked much better.