Can anyone recommend with absolute certainty a bag that will host an 11.5” AR with a Law folder and a Surefire flash hider?

Preferably one that doesn’t scream “I’m tactical please target me first!”

Are you looking to keep the stock folded or not?

Tennis racket bag.

I got one of these and it fits my 11.5" AR easy. Not sure how much more the folding adapter and muzzle device add, but I've probably got an inch to spare in mine.

https://www.first-spear.com/noveske-discreet-backpack

I’d like to keep the stock folded

I've got 3 of these. A black 24" FDE 28" and just took delivery of an ODG 32"

Fantastic bags (for me anyway..) They might scream tactical more than you want though..

Savior Range Bags

Have you looked at the 5.11 Tactical AMP 72, it says the rear storage area is 24”H x 11”W x 2”D https://www.511tactical.com/amp72.html.  Also, here is a video and if you jump to 7:12 they guy brings out the bag and puts a DDMK18 with the Law Tactical adapter into it and it looks like it has about an inch or so at the top to spare https://www.youtube.com/watch?v=hNB77YpQe44 .  I just picked it up and like it a lot, I took the velcro molle off the front because to me it screamed "gun bag" and added one of their small organizer pouches on the front to cover up the velcro.  Pretty much looks like a regular backpack with plenty of room for just about everything.

I’m in the same boat and am considering the Vertx gamut 2.0 or Vertx gamut overland.
I think the Gamut 2.0 main compartment is 21” height and the overland is 26.5” height. Could always measure the AR when folder and look at dimensions of bags to see if it would fit

I've got a Vertx Contingency Duffel 45L that I use for a BCM 11.5 with a Law folder and a T-2.

Folded it fits into the side pocket with just a smidgen to spare or I can stow it in the top main section if I want to.

https://vertx.com/contingency-duffel-45l

Pretty handy bag with lots of spaces for storage and doesn't look like a "gun bag" to the average person.

A 11.5 with a Surefire CTN with LAW Folder measures 22" from the rear of the Law Folder to the Edge of the Surefire CTN. Add 1/2" for the locking tab on the Law folder. 22' from muzzle to back tip of grip (Magpul MOE).

Looking at the dimensions listed the Contingency Duffle would work its listed at 22" for the compartment.

It looks like a gym bag and you can access most of the contents without exposing the end panel with the concealed compartment. Has what looks like pack straps so backpack carry isn't out of the question. Comes in blue hipster heather. @WKGTRS maybe can answer this one - Not sure how much a gun would poke into the main compartment and take up space. Might be "off" looking unless you are a gym guy.

The GAMUT 2.0 lists the compartment at 21" straight and 22" on the diagonal. Not sure if this would work for all but the most stripped down slim hand-guard 11.5 pistols/SBR's with a folder and not sure how it would work as the grip will be pointing to the top of the pack.

Looks like a everyday pack someone uses for work from a distance. Has the adjustable interior sleeve in the main compartment and the concealed carry pocket next to the body both lined with velcro for mags or a pistol. Any folding SBR/Pistol will eat up space on the interior. Unless you have a smaller gun or have some sort of fabric velcro edged cover made it would appear the folding SBR/Pistol might be visible when you open the pack. On the muzzle end if it has to be diagonal maybe one of the tactagami things could be used to minimize snagging when getting it in and out.

The 5.11 AMP is listed as having a 24" rear compartment which would fit.

It looks like a everyday pack from a distance, of course 5.11 has to put 5.11 stuff on it so a few minutes with a stitch puller might make it blend in slightly better when you get that square velcro patch off the flap (if its stitched on). The back compartment seems like it would fit, protect the gun and allow good concealment of it, plus not bang up a laptop if you have to carry one of those. I checked one of these out the other day and did not notice a concealed carry compartment for a pistol.

Just my observations and thoughts.

ETA: What about the Vertex Check Point? Interior is 21.75"H and 22.75" Diagonal Length.

ETA 2.0: I can confirm that an 11.5 Pistol with a SBA3 and Surefire CTN with a 20 round magazine will fit in the 5.11 AMP 72. It is a slightly tight fit but it does work. The 24" 5.11 advertises has to be the diagonal measurement. Would work perfectly with a 10.5 or 10.3.