yeah R&R is gonna eat locals and wardogs in 1-2 shots, it does 80-90 damage so it makes sense that it insta-downed you. Your team had 3 squishy characters and the Kon didn't seem to have a clue, he could have bubbled the antag off near the end there, his gun also shreds Alicia. Hades characters also work fine against it, they have more health and survivability oriented powers.
Now for Tolchok, that gun is outright broken. Your only real hope is to out-maneuver Konstantin, using jetpack, stalk, or teleport