Buy two good front speakers that fit your room, then get some cheaper ones for back speakers. Get a monitor that can drive them. Then, think about maybe getting a center speaker, and after that maybe the extras needed for 7.1. You probably won't bother with the last step.

If you don't care about any of that crap above then get whatever soundbar is convenient.

Sonos brick old speakers, and they're overpriced. Avoid.