I think I'll chime in here a bit. As someone who doesn't play HazardStack.pkm, and pretty much always just relies on Stealth Rock, SR is VERY powerful. Nothing in the game is immune to it (without HDB), and Pokemon of various types take reduced/additional damage from it. SR is a consistent threat to any given team, unlike Spikes or Sticky Web, which spawned the "Superman" team style from Gen 3+. (Mass Flying/Levitate Pokemon to negate Spikes/Webs threat.)
However, like with Spikes/TSpikes/Web, SR has a few flaws to it as well. We have a number of ways of removing them (Rapid Spin, Mortal Spin, Defog), and they can be no u'd back into your face (Magic Bounce). HDB on various Pokemon also helps against this, especially on your Spinners or Foggers. One more layer on top of this is any Pokemon with Magic Guard (which doesn't exist yet in Gen 9) completely ignores those hazards (even though TSpikes still poisons you, but that doesn't matter since MG prevents poison tick.)
Do I think Stealth Rock is broken? No. To call SR broken means you're unwilling to adapt to it and run a Fogger/Spinner/Bouncer. Yes, there are plenty of times where we just need to deal with the hazards because our removal is gone, but that's just Pokemon. You either played bad and lost your hazard control (speaking from experience) or the matchup was bad enough to the point that you had no control over them at all.
Seriously, we have SO many things that works as a form of hazard control.
Magic Bounce - Hatterene, Espeon
Defog - Corviknight, Talonflame, Scizor, Altaria, Lurantis (not that the last two are even relatively relevant.)
Rapid Spin - Great Tusk, Iron Treads, Quaquaval, Tsareena, Toedscruel, Donphan, god forbid you use Torkoal...