No.
Allow me to explain. It would be a REALLY bad idea from a narrative standpoint to introduce this idea. If it IS possible for a Darkin and a host to co-exist all nice and cuddly together, that would be cripplingly bad for the lore and story. It would ruin the idea of the Darkin as flawed, tragic monsters driven to insanity and evil by what they endured fighting the void if one of them just kinda.... got over it and decided to be nice. It's like "Hey Aatrox? You'd stop suffering if you just hugged it out with your hosts man." It downplays the curse they all suffer AND how powerful it and they are if someone can overcome it and just kinda... exist.
Take for example... Kai'sai. A LOT of people felt (myself included) that her story and lore REALLY diminished the void as dangerous and threatening. After all... Before Kai'sa the void was a horrible, alien realm that rendered everyone and everything that came in contact with it corrupt, insane or both. A POSSIBLE exception was Kassadin, but the dude is VERY obviously inhuman and his exposure to the void has clearly affected him very deeply.
Then Kai'sa saunters into the void and back out again and it turns out all those other people who went mad from sniffing the void's farts just didn't want to be sane enough. That fishman from the Nami comic? Malzahar. Kassadin. All the darkin, ironically... since the void was what drove them nuts. Didn't ya know all you need to do to be okay is just stab a void monster and wear it as pants and you'll be 110% mentally stable and okay? Even if it's just that no one thought to wear a voidling as a hat before, it still REALLY diminishes the whole thing to know that Aatrox, Rhaast and all that darkin nonsense could have been prevented if anyone had just made some void beast boxer shorts and handed them out to everyone. And if the suit that spared Kai'sa her sanity and prevented her from mutating is just like.... super-ultra rare and unheard of before then it doesn't fix the problem... it just makes the void look weaker and Kai'sa seem like she got an EXTREMELY lucky deus ex machina dropped in her lap. This even makes HER seem shittier, since now instead of coming off as a plucky survivor that went through something VERY close to literal hell and survived... she seems like someone who just got handed a lucky plot device so that the writers could have her stay all pretty. (That is ACTUALLY why Kai'sa looks like she does to be fair.)
So anywho... whether or not this is a possibility in the universe of the game it should NEVER happen. It further downplays what is supposed to be a huge, important plot point that many, MANY parts of the lore are built around. This is not to say that Riot will avoid doing it though... they've pretty regularly made some god-AWFUL narrative choices when writing lore and stories for the game and it's characters... and they've already kneecapped the seriousness and crfedibility of most of the things that were supposed to be massive, overwhelming forces or threats to the world or it's characters... so who fucking knows anymore?