Help me out: Fast hiking/trail running pack

Ok folks, help me out here.  I'm looking for a fast hiking/trail running pack with the features below.  

(Note: no dedicated treail running "vest" has ever fit me well or felt remotely comfortable.  I am 6' 4" 205 lbs with a long torso and a genrally muscular/athletic build). 

-About 15-20 L capacity...a little bigger/smaller OK

-Availble in M/L back lengths

-Fits/carries comfortably

-Small pouches for snacks on waist belt

-Option for water bottle/flask carry is a bonus

Ideas???

USWE packs 

+1 for Uswe packs. Only used the smaller capacity running vests, but it’s been a game changer. Would compare that to Ultimate Direction’s fast pack line. 

I absolutely love my Black Diamond Distance 15. It's tough as nails, has so many pockets on the vest, and is comfy over many miles 

Ultraspire Epic XT. 

Salomon Adv Skin 12, XL size.
I have their previous generation and its so good I bought 2 because I was worried about them disappearing during the pandemic. Their current generation has a different back cargo space setup with a quick stash pouch behind the head for a jacket or something. I stash jacket horizontally low across the back channel.

Old gen:
https://www.salomon.com/en-us/shop/product/adv-skin-12-set.html#color=39820
Current gen:
https://www.salomon.com/en-us/shop/product/adv-skin-12-lc11657.html#color=76900

Unfortunately that doesn't give a good example of how much you can load it down. If you can get your sleep setup very very small and light, like UL bivy bag, UL down bag, UL inflatable pad... it could all really fit, barely... but without food resupply you would probably be limited to 1 night adventures.

2x 500ml soft flasks and 1.5L bladder. 600ml soft flasks fit, that's what I switched to. If possible take a filter flask cap (either salomon's or BeFree) and try to cut some water weight.

Can fit a stupid amount of calories in the front, front side, side, and back. Not bad to pull out a stashed jacket from the low back compartment, but not the easiest to stuff it back without taking the pack off, but I manage it and I'm certainly not all that flexible. Its a very very popular option for trail runners doing Grand Canyon Rim2Rim2Rim.

Only mod I make is reinforcing the sewn on hang loop because I like to leave it hung up, loaded up, and ready to go.

Salomon XA-25 is another option, though kinda hard to find in the US. S/M and M/L sizes, and the M/L size is apparently pretty big. Comes with two 500mL flasks and checks all your boxes (except its slightly more than 20L and has vest pockets instead of on the waistbelt).

Folks, thanks for all the suggestions so far.  

Some of these rigs look amazing (USWE?!) 

But as I said....any kind of vest system is just a non-starter for me.  It feels like I'm wearing a basketball up between my shoulder blades....not comfortable at all.  

I'm thinking more a lightweight backpack with waist belt pockets...something like the Salomon pack below but avauilable in L or XL backlengths.

More ideas?

https://www.salomon.com/de-ch/shop-emea/product/trailblazer-20.html?CMPID=pla%7css%7cgoogle%7cCH_DE_GOO_SMARTSHOPPING_PERF__Bestsellers%7cCH_DE_Bestsellers%7c%7c467751565888&gclid=Cj0KCQiArsefBhCbARIsAP98hXQTULYyBjpzd9oW5H_HEh6YrRK_1Q0Euy8Md1flnInbASOZul1woQYaAnulEALw_wcB&gclsrc=aw.ds#color=47637&size=27102