Turbo is great. It allows you the best of both worlds. Why have less features and a less capable flashlight? You can always choose to use a light at a lesser capacity
Here’s a review, in Russian, I believe, but on the minute 1m10s you can pause the screen to the user manual description of the operation/UI.
I am not sure I am a fan of the UI, and I would like to change the driver for something different in case I had this light.
But I guess for a simple UI, and good build quality, you can’t ask much more. Also, it says on the manual that output decreases to 40% when the light reaches 60ºC . So…I guess that keeping it “cool” will probably maintain the output higher for a longer period 
Might be a long wait. Looks like it’s now available . On high (40) mode you get around 2 hours of runtime (tested by Zozz lights if memory serves). The M3 only starts to generate heat on turbo (100). Maybe it’s designed for good outputs and runtimes rather than the “wow” factor. A humble Convoy S2+ can nearly match the lower modes for output but then high mode is not sustainable on those.
Ramping is definitely the way to go with high output torches. But having modes is better than having none at all.
Maukka did say ZL’s specs are exaggerated just like almost every other flashlight brand. I personally tested many hundreds of flashlights and several different Zebralights so I am familiar with their specs vs actual measurements. Don’t get me wrong, I like Zebralights and I like Acebeams and own a bunch of them, but it’s a fact their lumen specs are exaggerated just like 95% of all flashlight companies out there.
I tested a few TC20 and their specs are usually 20% exaggerated. Also from all the Thrunites I measured, their tint is way above the BBL resulting in greenish/yellowish tint, which is especially noticeable in NW versions. The Thrunite T2 is the only single cell light I know of that can sustain just over 1,500 lumens but the beam is horribly green and the egg yolk tint shift is just awful.
The Convoy M3 and M21U are the single cell lights on the market closest to achieving the OP’s required specs.
The upcoming Fireflies E12R with 12 emitters should theoretically be able to exceed the OP’s specs with their high efficiency regulated driver assuming you choose the XPL2 or LH351D option but until it’s tested we never know.
1lumen.com and zeroair.org have the most extensive collection of runtime curves.