git gud.
Depending on what map you're on you may be able to sneak up behind them, arowana mall for example is a great map for ambushing snipers. a lot of good charger players have really good map awareness and pay attention to the map, however you can use this to your advantage, Don't ink any turf on your way over and they won't be able to see you coming, then you just sneak up behind them and splat them before they even notice you're close enough. the way you get splatted by burst bombs is the eliter has realised you're too close before you've had the chance to inflict real damage on them.
If you play a weapon with the sprinkler you can disable a charger or splatling by throwing a sprinkler next to them. They have a few choices, Retreat, Die by sprinkler (honestly super embarrassing) or destroy the sprinkler. if you submerge as soon as you throw the sprinkler you'll have enough ink to throw another one and then they'll have to repeat the process. This does require a good team to back you up. you're role in this match for now is to enter a stalemate with the charger, which can be extremely helpful, maybe even more so than plain out splatting them. A splatted enemy gets to try a different approach.
If you play a weapon with splat bombs or suction bombs, abuse that too. chargers are pretty used to retreating to that option, but it does push them back at least temporarily. you can also use splat bombs to at best trade with a burst bomb seizure. if you throw one down at your feet when you're within close range I've found that the burst bomb seizure takes too much of their concentration and they'll end up getting splatted.
a killer wail is a great way to remove a charger from it's perch. try to also cover their getaway option for a splat.