Hearthpwn

So as kid I grew up with labs and huskies; My military years were occupied by the obvious 2 breeds. However this more geared to "normal" upbringing of a dog. i've always loved BIG dogs over spawns of satan. My choice after the experience I had; was a great dane (it's3 now.) but my quam is the stubborn streak; I can't break it. They want the walk on their time, not mine. (I tried scheduling it for coffee time & before dinner) They literally go out anymore but have an hyperactive indoor spree. This ain't something I learned to correct; what's the solution? They're about 3 years old now so puppy 101, etc is gone.

This might need a side-story their "leader" not me got severely messed up one day on a walk by a snake. That was a 5 month break period and he still ain't pretty where the bite was.It kind of fucked the pack mentality because the one I chose isn't willing anymore. So how do I establish dominance for one among 3 when the older one previously dominant one helped raise the others? He was severely fucked up by the snake it was 3 months of fighting necrosis and infections; another 8 until his wound fully closed and scarred over. Their dynamics have swapped from content to fighting; I won't lie I've physically stopped that twice. The coexistence however no matter what I do; they're actually fighting, and I'm coercing them to sleep together, etc. but there's this persistent dominance struggle now. They're constantly testing the water from bitey-face games to actually having to gut-punt one when it's overboard.. I can teach a dog shit, but this trio is actually beyond my comfort zone. I'm debating a new pup or actually ending the next scuffle with an actual frowned upon beating.

Edit: the gut punch above is true in a way; It's more of "takedown" picking one up and a timeout albeit by the gut area since they're fixed & stomach stapeled.  They have dog to dog disdain; I'm the net plus+; any advice beyond an actual beating would be appreciated. It's  near that point.