@DonGiovanni probably sleeping in game helps your real body as much as drinking in game does: zero, maybe you can relax to boost your concentration afterwards a bit, but his real body will be more or less awake and yes the dehydration is quite dangerous, especially since he already was for a unknown time online before and he probably also didn't drink this much before entering the capsule -
don't know how this capsule is supposed to function, 20hours of continous using should already not possible since your body will need to go on the toilet at least once and dehydrating yourself in advance would be very bad too
and I agree with others here, about no likeable characters, this tsedakah guild members seemed to be okay and some of the npcs like this steim warrior or our smith here, it's a game world, so of course the players can play way dirtier as they would irl and Grid and others show potential for development ( I see a death flag for his grandpa) but it would be nice to have at least one person you can truly like