The irony is that not stressing the car is actually damaging your car right now versus the hypothetical damage from stressing the car. And not just in theory, since you've reported knocking and pinging.
You can imagine even if you don't have knock, you are close to it and the knock sensors are kicking in, which must mean that at least a couple knocks happened before the sensors changed things up.
It's like in the movies where a guy won't talk because he's afraid of what his boss will do; and the hero says "your boss?, you should be afraid of me!"
If you didn't know, that's fine; but now that you're informed by your mechanic, perhaps you can imagine black crusty soot and carbon crud growing on your valves and you need to flush it out, versus the engine shaking itself to bits and you'll be more OK with it.
Also, maybe try redline or other products too. For me, even though redline is more expensive; I've found that I can use 25% or 50% of a bottle over 20gallons with similar result, so that lowers cost (premeasure it into a 2nd bottle first).
Longer more frequent treatments at lower doses might work better for your then the one time treatments.