Hi guys!
As this is my first post here, wanted to say hello in the first place
I've been reading this topic and helped me a lot to understand the difficult path to get the 279e, so wanted to share some experience in return. This will be regarding crit missions, as I think I managed to get quite consistent results in the current meta.
1) First option is to play with a big gun
For Chimera Union 8 this will be SU 152 with 152 mm ML-20 gun. Load premium HEAT and enjoy the ride. It's a less consistent method than the next one but it also works. Try not to one shot enemies,