Frontlines is already a mode that constantly tries it's best to put that "Why bother?" mindset in players. Fixing that itself is a whole other can of worms, but the people who are already dedicated to grinding out XP/crystals/marks through minimal participation are still going to put in minimal participation if the baseline rewards for losing a match remain the same. Nothing will have changed for them, they're still getting their rewards as they would have always been getting. You're just not going to make that handful of people in Onsal Hakair who afk on the ovoo closest to their base care enough to stop afking, unless you take away their incentive for doing so, in which case they'll probably just leave and, just maybe, be replaced with someone who actually wants to play the game.

Drastically slashing the rewards for a loss could help with the people who just don't care, but I think we all doubt that'll happen.

That said... drop Frontlines to 48 players and remove rng objectives, Yoshida.