So if you have a conc pot, you just pop 2nd Hunter’s Prowl as soon as boss get’s close to you, that is that simple! Also the boss should be AT LEAST half-dead at this point.
With speed pot you delete bosses in 5 seconds, so there is NO WAY that he gets close to you.
And if you have problems killing bosses without pots, here is a short guide for it. It’s for Slayer, but basic idea is simple - wait till allies lure boss a little away, then make it implode.