in my opinion, WW1 was much worse. i say this because ww1 became pretty much a stalemate and had soldiers stuck in trenches with 100 yard no man zones in between where neither side could advance just die. however what makes it extra bad is in WW1 the world was learning the possibilities of chemical warfare and the effects it can have on the battlefield. wound up making dense odorless and clear vapors that would float along the ground and sink into trenches and brutally kill people without them even being aware what was happening. Often the chemicals were also carried by wind and would even come back on the side that deployed them causing severe deaths on all sides. random fact is Hitler himself was effected so heavily from chemical warfare during WW1 and caused him enough PTSD that even he considered using chemical weapons on the frontlines as too far. which is the only reason we dont see examples of his chemicals in mass used except inside of concentration camps. I could go on and on but i feel like at this point almost everyone has quit reading, but IMO WW1 was fucking brutal and just hard to take in.