Deep Litter is gross while you figure it out... FYI. ;-)
It is not impossible to have DLM on concrete and there are some great scholarly articles on it if you do a really intensive search (including google scholar) you’ll find information about it.
Aart said ALL the same things to me in my quest for deep litter on concrete. I actually am a pretty skilled composted with horse manure and pine shavings and I measure temperatures and moisture so it made sense to me to try.
I don’t find a barrier entrance difficult at all. You just step over it, mine is 2 feet tall.
I went to a LOT of trouble to figure out exactly what carbon/nitrogen ratio I needed but as 
@aart has preached already, it’s all about moisture. Too much moisture and you’re in a REAL mess. Too little and you’re going nowhere fast.
I personally found that it’s too gross while you’re figuring it out. Without the right moisture, I had nothing but dry pulverized 18 inches of manure and shavings in my coop. And the top level? Don’t get me started. You’re constantly walking in poop and getting big clumps stuck to you. My chickens do a FABULOUS job of s ratching and mixing it. So what. They’re bringing yesterday’s poop to the top and putting today’s elsewhere. You still step in it. I’d rather clean more often.
And my LAST straw was the realization that I probably was making my chickens unhealthy for me. Deep litter with just pine shavings and other light items means you cannot keep your chickens from wallowing in it. Gross. Eventually it’s nothing but poop they’re rolling in and even if you don’t handle them, the thought of what they’re shaking off when they ruffle their feathers.... well... It just doesn’t seem healthy.
I firmly believe it can be done. I just don’t have the time to micromanage at the level you need to to figure it out.
I have personally moved to deep bedding in my coop/run combo. GAH I should’ve just listened to Aart. ;-) I find I spend less time with a small clean out weekly, and a monthly or so larger clean out, than I was picking poop off my shoes.
Good luck. I may try and find some of the articles I used for my research if I have time during toddler nap time today!