I am reading you correctly because you said in one comment that the boss is “asking a level of play and coordination of a 29+ on a 22+”, then in another several hours later that “You don’t notice it on a 22”.
That’s backtracking on your original claim.
However, my point was that there are other things in that dungeon that will one-shot groups on a +29 if their group comp, comms and coordination of interrupts and stuns aren’t perfect.
You can (legitimately) argue that balancing is far from perfect, but I don’t believe there’s any intention to balance around +29/30 keys. From what I see, I think balancing for M+ is generally aimed at around the +20 level. People doing +29/30 keys should expect weird things to happen.