Looks like I found the match:
my betaflight rates settings:
RC Rate: 1
Rate: 0.8
RC Expo: 0.2
this gives the max rate of 1000
I overlaid a graph from FPV Freerider over a scaled screenshot from calculator at rates.metamarc.com, and found a match with following settings:
Max rates: 1000 (it's actually 1003 from Snappy3 preset, I can't make it precise with a slider)
Expo: 0.2
Superexpo: 0.8
My conclusion:
looks like your superexpo is BF Rate, and your Expo is BF RC Expo :)
With this graph overlay thing I was able to tune the drones to behave same across different sims :)