Empire of Humanity

Aside from the anti-religious bent, the games setting is fairly standard space-opera scifi.

Technology is advanced enough that it recedes into the background - computers are hidden servers with voice query rather than towering difference engines or huge banks of flashing lights.

Laser guns look like video equipment. Small ones are all but indistinguishable from modern camcorders, larger ones would be like whats used in a professional studio. Knives and short swords are popular as most people can't afford/acquire ranged weapons - and the lasers have a tendency to cause collateral damage.

Great disparities of wealth exist, and a nebulous alien threat exists just beyond the borders. As such, spirituality continues to exist as both apocalyptic hope bringing forms. Some use it as a link to the past, others don't even remember what it means - but the weird costumes and stained glass are intriguing.

FTL is averages about 1.5 light years a day, placing the various planets a few weeks apart for fast ships. Messages must be sent via courier. Thus if a planet rebelled it could be months before anyone learned about it. Hence the attempt to avoid things that could start such discontent - like differences over celebration.

Most planets are following a trend towards ecumenopolis ("city made of the world" - think Corosaunt or emperor's world in Foundation) but there is still green space. While interstellar travel is fairly rare for the average person, subways and hypersonic aircraft mean world transversing trips take less than 10 hours.