Ok, and I'm really trying to grasp the difference but I'm not seeing it... don't PC's in D&D have numerous class abilities, magic, animal companions, team synergy, etc to in turn do the same thing. As a simple example...couldn't teleportation or invisibility spells/scrolls/rings have just as easily circumvented the stealth issue in D&D?
I don't know how you don't see it.
But I'll start with the easiest parts:
1) D&D Groups are typically 4+ Characters. A Stealth Group Check becomes much more brutal in that scenario where 2 characters has to pass the DC (a DC that the GM has to extrapolate vs it being an always known spread of success/failure model), particularly when one or more of the PCs likely have heavy armor and are going to be rolling with Disadvantage. Even if this was 4 Blades PCs, as long as one of them gets a 4/5, that is at least a Success w/ Complications. If one of those 4 Blades PCs (if there were 4) get a 6 (a virtual lock), its a Success. The question just becomes how much Stress does the Leader take. So you've got multiple angles here:
(a) The players are beholden to the GM's conception of the situation for the Stealth DC. They could easily put a number out there that ensures a massively higher % of failure rate compared to Blades. Blades PCs don't deal with that. The spread of results is always known.
(b) The possibility for success on a Group Check increases as more PCs are involved (better chance of rolling a success and more resources to martial) and the inverse is true in D&D 5e, particularly on a Stealth check.
2) There is no Stress analogue in 5e for martial PCs to marshal to increase their effectiveness (and simultaneously that they have to manage/ration) in play. Inspiration isn't the same thing operationally (its attainment/maintenance) or in spirit or in execution (if you're lucky to have one at this moment thats it...fire and forget and hopefully you can get another one later...vs a pool to call upon and manage) and it doesn't appear to be stock 5e anyway as it seems like the bulk of tables don't use it.
3) There is no analogue for Position/Effect negotiation in 5e. GM sets a DC, that's final, and you don't even know if it will be table-facing before the roll! And the GM tells you what to roll and if your Skill Proficiency applies. None of this is like Blades at all. Its the opposite in every way.
This one is HUGE. In 5e, what is happening is the GM is saying "you're going to have to make 3 * successful Group Stealth Checks to get across given the length of the bridge." That was going to be the case initially (the Limited Effect), but the players did a bunch of Blades-specific stuff to increase their Effect to Great so its one Group Check to get across.
I mean, maybe in 5e the players say:
"Can we sprint across stealthy as a group and cover that distance in one Group Check?"
To which the GM extrapolates based on their conception of the situation (rather than using the binding procedures of play) says:
"Uh...sprint across...stealthily? Uh...ok, I'll be kind and let you do 1 Group Check Strength rather than just reducing it to 2 Group Checks...I'll let you use Athletics if you've got it...but this is going to be at Disadvantage to sprint across stealthily. This path is narrow + its wet + you're somehow trying to sprint across it and not make a noise. So DC 20 w/ Disadvantage."
To which the Wizard player might say:
"Can I use Silent Image to distract the abominations to give them the time to sprint across quietly?"
To which the GM might say:
"Sure. Int check vs your save DC. If they both fail, I'll give those without Heavy Armor Advantage, offsetting their Disadvantage. You guys with Heavy Armor though? No way. You're plodding. You need extra time and you're making a lot of racket most likely."
I mean...the odds of success for Stealth obviating this first obstacle and setting up Team PC for the next obstacle is just absolutely remote.
Unless, you've got a 7th level Wizard that (a) has Invisibility and (b) wants to uplevel their Invisibility to 4th level so all 4 PCs (assuming there are no more than 4 PCs) AND the GM doesn't invoke the "but what about the move silently part" clause and therefore forces you to make 3 * DC 10 Dex Group Checks w/ the Heavy Armor characters having Disadvantage.
I mean. More than likely, its just going to be a spotlight tailoring deal in 5e where the Rogue goes across by themself and ganks a guy while the other characters act as artillery and fire ranged weapons after the initial gank.
Or maybe the Wizard does something with Mage Hand if the idol is light enough.
Its just that what will invariably happen in 5e D&D (both what will be reasonably permissible and what the go-to power play will be) won't look like Blades in the Dark and it certainly won't be operationalized like in Blades in the Dark (the cognitive workload in decision-point navigation by individual PCs and by Team PC as a whole will just be fundamentally different...least of which because the GM's conception of the fiction and extrapolation of difficulty is primarily governing the difficulty and permissiveness of player action declaration input).
That to me looks like a very likely scenario for GMing the situation in 5e D&D. The odds that the PCs are successfully capable of defeating that obstacle with Stealth alone are WAY lower than in Blades. And the decision-point navigation + the resources that martial characters can call upon + the Group Check math + the table-facing vs GM-facing nature of play + the GM conception of situation yielding DC/Adv/Disadv/what you can use and how it works vs orthodox Blades procedures creates...
...all of that fundamentally changes the menu of decision-points, the navigation of individual decision-points, what is consistently able to be accomplished (and therefore the reinforcing mechanism of winnowing options that are even attempted to improve the gamestate for Team PC), what is reasonably able to be accomplished at all.