This manga deciding that Hell is actually eternal suffering and not something else would be a pretty jarring tone shift; I doubt it's really that bad. If bad at all.
It's actually slaving to death in a 7-to-18 office job doing nonsensical tasks at the whims of a supremely incompetent nincompoop who reflexively kicks down whenever confronted with the limits of nepotism whilst your peers conspire against you in corporate eat-or-be-eaten culture.
He's glad he atleast got a succubus wife out of this.