Depends on what the pressure looks like. A lot of Gargos pressure though (especially of the minion variety) isn’t DP-able. By the same token though, a goodly chunk of it isn’t shadow counterable either, so Fulgore’s disadvantages there are basically moot. Sometimes you’re just going to have to block it out - a lot of the nastier pressure options in KI shut down reversal attempts of all kinds.
Block. Once Gargos pops instinct and has advantage, you’re forced to deal with him. Well timed backdash might work too.
See the above.
EDIT: You can also DP Arbiter out of his pressure if he’s being extremely aggressive. You won’t even be punished for it so long as you do it early enough that the grenade doesn’t explode while you’re airborne.