The reason you have to have the wink wink nudge nudge is series like Berserk are so comically over the top, so horrifically horrible with every character being an absolute monster of a human with no morality or hope, just endless bloodshed and violence, that is becomes nonsensical. The "good" characters are every bit as evil as the "evil" characters there's no real difference, and indeed in a lot of Grimdark stories there is no difference. At least in 40k the Imperium doesn't have the self awareness to know burning a billion people at the stake is wrong.
That's... not what
Berserk is though. Not telling you to like it or anything, but it's not top to bottom awfulness, torture, and rape. The very beginning is when the story is most "grimdark", but even there not every character is an absolute monster. Really only Guts and the two apostles are - everybody else is just kinda caught in the crossfire. And then there's Puck, which if you're looking for wink wink nudge nudge, or a break from the grimdark, that's pretty much his entire purpose. You can dislike his presence, but you can't claim his presence only adds to the edgey grimdark atmosphere.
Then there's the Golden Age arc. Probably one of the largest arcs in the series and the one most fans site as the best part of the story. And while there's the obvious ominous endpoint that hovers over it and a few shocking moments dotted here and there, to say it's all top to bottom hopelessness and grimdark is completely false. Most of it is super relaxed and people getting to know eachother and forming bonds within a medieval war setting.
And if you want the story poking a bit at itself there's the combat violence, specifically evertime Guts really kills anyone or anything. When he's swinging a giant sword while standing in a house, smashing it through the door frame and into a pig monster, that's not to be taken seriously, that's the story going 'look how insane this whole situation is'. It's equal parts epic and funny. Same as when he's riding a horse full gallop with his sword out and whacks an incoming dude on horseback into the air. Even the infamous rapehorse is purposefully goofy. Yes, it's fucked up and shows Miura was a bit to eager to have his demons be rapey, but when a horse with dopey human face says 'how about I mount you' that's not the writer trying to display some deep, profound message, that's them having a bit of fun. And everytime Guts is in battle, apart from a couple of more 'do or die' moments, it's cool and silly on purpose.
If all you've ever read is the starting Black Swordsman arc I can understand you thinking that's all
Berserk is, but once that's over, which it is quite quickly, that particular style of grimdark pretty much never returns.