everybody thinks ilya and shane have diametrically opposite sleep styles: shane is in bed by 10pm and is super intense about his sleep hygiene all year round, and ilya would be completely nocturnal if left to his own devices, and survives on sugar and coffee and naps during the season.
but i would submit, based on some evidence from the show, that ilya is actually one of those people who really need and are inclined to be in bed super early. sure, he'll go out late a lot, but when he's at home, he's asleep, full snork mimimi conked out, by 9pm at the latest. and when he's out, he is OUT. you're getting nothing coherent out of ilya rozanov until he's had his full 8 hours.
shane is the one who has to work to fall asleep. his natural inclination is to stay awake and ruminate and stew in his anxiety, and he maintains his sleep schedule by the skin of his teeth using meditation, melatonin, blackout curtains, and a white noise machine. and he still wakes up frequently. 8 hours in a row is pretty rare for him.
and he really figured ilya was the type of person to be on his phone scrolling for hours, up late making snacks and playing video games and just generally being a night gremlin. instead, the first night they're at the cottage together, ilya starts fading at around 8:30 and eventually shane is like "should we go to bed?" and ilya is like "no no no, i am awake. i heard everything you just said," which is funny because shane didn't say anything. shane was prepared to just throw his sleep schedule out the window for ilya, but instead they're in bed almost before the sun fully sets and ilya is fully, totally asleep before shane has even finished setting up his water bottle and ear plugs, just in case.
but he doesn't need them because being in bed with ilya turns out to be the perfect sleep remedy. shane sleeps better next to ilya than he has his entire life, and not just after he's been fucked through the mattress either. it's totally addicting sliding into bed next to ilya, who is already dead to the world, and getting to wrap his arms around him and listen to his tiny snores and, once in a great while, ilya will wake up just enough to grab shane's arm and pull it tighter around him, or if he's spooning shane, he'll mumble and kiss shane's neck and snuggle closer.
shane is very protective of ilya's sleep, especially after he sees how much he needs it to function. a sleep-deprived ilya gets lethargic and depressed more easily, finds it hard to eat right, and is way more clingy but also grumpy. so shane becomes the guardian of ilya's sleep. any of the team need to talk to cap? it's not an emergency, come back later. yuna has a question about ilya's contract? ask during business hours. ilya's phone is on dnd from 8pm-8am and nobody's getting past it or shane, the human dnd. try to interrupt his baby's rest and you're getting blocked.
and ilya (always kind of embarrassed by the fact that he's an early sleeper and early riser, it's so far removed from his image) loves to have shane take care of him but is also incredibly relieved that he can blame it all on shane's healthy influence. no, rookies, he cannot go clubbing tonight, he is not allowed. is terrible, but you will understand when you are married. meanwhile an hour after they get home ilya's cocooned in their down comforter, moisturized and hydrated and making happy little falling-sleep noises waiting for a goodnight forehead kiss from his husband.