I found that your + core number doesn't always mean higher is better.
I tweaked around with my numbers significantly and found that there is, at least on my card, a sweet spot where your clocks go high and stay more steady.
I can take my card to +175 and have seen it hit 2175 or 2180 (cant remember) but my best bench is when I set a +155 and 1200 mem.
I spent a week tweaking things, including lowering my CPU overclock just a smidge. Doing that helped prevent some of the crashes I was seeing at higher gpu clocks.
Like I said this may be my card specifically but it's something to look at when trying to get both stable and higher clocks.
https://www.3dmark.com/fs/17071737https://www.3dmark.com/spy/5060821