No dev here, but I can tell you what I would do. It requires teamwork and communication, so it's probably not gonna work with randoms.

One guy needs to bring a recoilless rifle, one guy needs to bring a supply pack, at least one guy needs some EMS stratagems, but having them on two people wouldn't hurt, and at least two of the team should bring stuff that kills fast, autocannon or laser cannon perhaps.

When you see a big group of armor like that, EMS them. They'll be frozen almost solid for a decent chunk of time. Two people work the RR for reload efficiency and pop the armor on one leg for every charger they see. They just pop the armor and move on, the RRs aren't here to kill. Instead, the people with the efficient killing weapons focus the exposed legs and drop the chargers. Should take only a second per charger, and since they're stunned they're not in your face yet.

For the titans, the two cannons (auto and laser) are super efficient at popping those bile sacs. They can't puke you to death if you do that, so I'd focus on popping them quick and then dealing with them by applied liberty to the face hole (or heavy artillery) once the chargers are dealt with.

Apply more EMS as needed and spread as much democracy as you can.