Yes, and parties are invariably led by a high-Wisdom Perception-trained character, since players are not stupid.
So the DC monsters need to beat is 16 or 17. At first level.
Good luck finding a monster described as "super sneaky" that does not stand an overwhelming chance of failing miserably at doing the one thing it's there for: executing an ambush of the PCs...
About the stealthiest MM monster I could find at CR 2 or lower was the Shadow and its +6 modifier. That still means it fails more than half the time against a zero xp character. And its a frikkin' shadow. And even that assumes the party isn't bringing a lantern.
Tl;dr: the skill scores of MM monsters (mainly their Athletics and Stealth, but also Perception) is downright pathetic.
"So the DC monsters need to beat is 16 or 17. At first level."
Huh?
Point buy and str array gives you a 17 cap on abilities at 1st level. For +3.
Proficiency is +2.
That is passive percrption of 15 assuming that's the lead guy at first level.
So, a wolf being sneaky needs to roll 15 - not 16-17 - since contests like this have ties go to the prior status- the wolf was unseen before the check, so tie does not reveal the wolf.
With stealth +4 that's z toll of 11 needed do 50/50.
Flip the situation, PCs sneak up on wolf. Wolf gets advantage due to keen senses and so has passive per of 18.
That's gonna require that first level sneaker with +5 net bonus yo roll 13+. So, a little tougher.
Now, the outlier might be s variant human taking like observant at first or one of the dex+1 to get to 18 dex. But nowxwexare into very specific outliers, not routine play.
By tier-2 and lateer tier-1 with magic, this changes of course.