if you read like any of the popular W40k novels everything about the Imperium of man seems like unfettered dogshit

the majority of the people live in decaying hovels eking out a miserable agricultural existence or in enormous planet sized slums that have all sorts of issues (rampant crime, gangs, mutants, etc.)

if you're part of the actual government you are like an undying heavily bio augmented freak with an incredibly long lifespan (iirc Inquisitor Ravenor is like 300 years old lmfao) stemming back a tide of literally incomprehensible horrors that you aren't fully equipped to deal with

like in Caiphas Cain the entire point of the series is that he's a regular commissar who frequently stumbles into absolutely insane, fucked up situations and spends most of his time trying to run the fuck away because getting turned into some mutant freak by Tyrannids is in no way cool or exciting

god help you if you're part of the regular ass army