Current AI Difficulty: Largest Map, FFA, Orbiting and Non-Orbiting Planets, 5 AI on Impossible Difficulty

Has anyone played on the largest map with all AI on impossible difficulty with no teams?  I am curious if anyone else is just getting killed time and again.  I have played 20+ matches with the AI and I can't get past my own ~5 planet solar system before the AI comes and kills me.

I have tried to max out garrison on my home planet and research increased garrison count (but not up to heavy factory research option).  At one point I had 30-40 light frigates, one Marza, and about 150 garrison light frigates, and then one AI came to my home planet and quickly destroyed me with a few capitol ships, lots of light frigates, robotics cruisers, and percheon carriers (a ton of these).

I have tried to get a large fleet size (>200 ships) of light frigates, flak ships, and percheon carriers and to stay back out of the central part of the map, but again get killed by the same AI fleet config as they come to my home planet.  Minimal research up to civ level 2 and military level 3 just to get ship research and maybe some weapons research to help a bit.

I usually colonize the five or six planets in my solar system and try to get econ up and going to get my fleet created or garrison up and running.

Not sure what's going on here as I continually optimize my strategy for speed and garrison or fleet size, but can't seem to fend off the first AI wave.  I never get the chance to assault farther in the map as I just get everything going and the AI comes for me.

Any thoughts?