btw double swinging against these players is like kicking a hornets nest

Run.

If you predict they'll circle around then slash, you can run in the opposite direction of their circle. That gives them these choices:
a) Swing at your previous location (miss/reset situation)
b) Try to dash to the side of the tile in front of you and slash
c) Switch to gun.

If they go with A, then the situation reset and both of you are at a 'neutral' situation (either of you can approach)
If they go with B, you have a chance of predicting their chase and getting a hit in by switching directions and counterattacking (you kite/bait/counter)
If they go with C, it's a bit of a situation reset, depending on whether or not they're good/dangerous with a gun. But if they go with a gun, it's not a toothpick, so it's a 'win' for you. Can possibly turn into a B situation.

Of course, the counter to this is for them to predict which direction you'll run. If you don't gain distance and force them to break rhythm by moving, then the situation's no better for you.

*I wrote this assuming you were playing guardian/recon - striker can definitely open up enough of a gap to do a short-ranged 'reset'.

In any situation where you can get enough distance to allow you to start a slash before they reach you, you can turn that into a counter attack.