For the past couple of weeks or so I've been trying to win a FFA against all heroic enemies, however it seems that when an AI focuses its attention on me, there's no hope of winning. My current strategy in the early game was to rely on the UNSC's ability to out produce the Covies and to hopefully cripples opposing UNSC production capabilities. But once the midgame starts to roll out, my own production capability is suddenly matched by the Covenant's and I resort to pincer movements to waste the energy projectors and get a bunch of "free" MAC shots off. I continue the pincer strategy up till the late game then instead of maybe 30 ships total, it'll consist of three fleets, a bombing fleet and two attack fleets.
Composition of the attacking fleets:
1x Thermopylae
1x Valiant
3x Orion
2x Marathon
1x Autumn
1x Phoenix
10x Halycon
10x Athens
~30 Thanatos
15x Stalwart
x2 Cradle
Composition of bombing fleet:
x1 Phoenix
15x Stalwart
15x Charon
Usually in the end game those three fleets can take a planet extremely quickly but they can't hold off a counter attack at all. Then the casualties sustained from any significant engagement means I'd have to either sack all three fleets or lose my momentum and hope I can remake them faster than the AI can counter attack. So far its only worked well when token forces are left defending choke points, but as soon as I engage with a main Covie fleet, no amount of pincer movements will work since its usually a counter attack and I'll be out of position trying to repair or replace ships.
Are there any better tactics? Should I try and cut down on my attacking/bombing fleets to try and build a tanky bait fleet?