The man in the ivory tower even says under the railgun heading that they are aware that one of the reasons the railgun is popular is because other anti-armor sucks.

Respectfully sir that's like the only reason. Your CEO said on Twitter that the ass of a charger is not a weak point, merely an unarmored point; well all the same I need my partner to get the charger to face the other way to hit its butt since I need multiple recoilless rounds to kill it.

Mostly just "keep moving". If you spread out a bit, generally one person or group will take most of the heat while things are relatively quiet for the others. Heat team basically just has to keep running while the other team does the objective. If a bug hole opens up on the objective, run away and circle back. Chargers and hunters seem the most capable of catching up, but the hunters are pretty easy to kill. For the chargers, they seem almost hard coded to take a longer stagger if you dive out of the way instead of just moving out of their turn radius, so you can dodge a charge and gain a little more time to escape.

Don't underestimate smoke, it can be pretty handy in keeping things off your back. Call down supplies often, even if you can't necessarily get to them all. They have a pretty short cool down so don't be afraid to waste a few or take multiple if no one else is nearby. Honestly I wouldn't worry about bile titans too much unless they're on an objective (or are an objective). They can be outrun and will eventually lose interest, and their attacks have fairly limited range with a big windup.

Granted I haven't tried all this since the update so take it with a grain of salt. I do plan to try it again this weekend so I'll report back.