Test this on lower difficulties to not make high level groups suffer but this generally counts for all bosses.
Let them walk up to you with block up, wait for them to stop and immediately dodge backwards.
Once the slam has hit the ground walk up to them slightly and Dodge backwards when the swing is about to hit.
This way you can learn to keep a boss almost stationary. Always have block up, once you get more comfortable reading a boss you can do a charged attack as you walk up to it but don’t get greedy.
EXCEPTION GOES FOR TROLLS AND FIRE OGRES.
Trolls have a sweep where you can only dodge it entirely if you backstep it or pay attention to the arm swinging as one arm will have a safe zone.
For the overhead swing always dodge sideways or diagonally sideways, NEVER backwards. Unchained will get full vent from the sweep but make sure you know what’s behind you unless you want to go for a ride through a horde or off a cliff.
For fire ogres dodge fire sideways ofcourse, the sweeping arm backwards. Their aggro is awkward so don’t try to force them to stay in one place, don’t get greedyeither. The flames punish squishy heroes/careers way too hard.
It beats forcing your entire team to chase after bosses with people running like chickens.
Special note for chaos spawns, all attacks can be dodged with a simple backwards dodge except (partially) the 3 slam attacks where it chases you. Due to this make sure you know you have a way out, don’t get cornered and keep block up, time correctly and you won’t even lose one stamina dodging backwards OR TO THE SIDE (both work for this particular attack but alternate them wisely.)
Hope it helps!!