From what I have seen more voltage/power to Pascal just makes it hotter and worse at overclocking. Some of the overclockers out there recommend reducing voltage to achieve the best results. And as you noticed, running the highest possible stable settings can lead to lower numbers. Usually you want to back off just a little from the maximum stable point.
In my experience with this card and rig, the only things to have any kind of stability consequences is the Core Clock and memory clock speeds.
Putting Core Voltage on zero or 100 has no consequences at all, maxed out it did improve performance a little (if I'm not mistaken) while the power limit increase from 100 to maximum, which is 107, that had pretty good positive results.
In short, the only 2 variables creating potential instability are the core clock and memory clock, they are also the two variables who can potentially increase performance the most QQ
I suppose as has been mentioned, in my case, the only solution would be to find some other way to increase the power (which traditionally is what heats up the card but here I'm far away from any kind of heating issues).