Did 1v1 flagship match on a random ~60 planet system vs hard (I think loyalists). I had been spending zero on bounty, taking all pirate raids, focused on a cultural head start, used my flagship / colony ship to ninja asteroid belts / gas giants and we had the system split about 40%/40% for ownership when...
I got the warning after a few hours in about the Cannon being set up on what looked like their homeworld or next to it. I paniced lol. I had no idea how much damage they could do, did a quick wiki to see the defense is essentially planetary shields and Aux Govt. I had no idea how much time I had, I also made a push for the Cannon to see if taking out their world was viable.
I won easily(ish), but I didn't know how easily until it was over.
I had been saving quite a bit of cash so on the next pirate raid I ramped the bounty. Another thing I had done, intentionally and accidentally is through the entire game I made sure the outer planets became scout buffers. Nothing made it further than one planet in.
After the game was over I had seen the effects.
First planet that they targeted was the pirates...and I saw why. I had forced such a large bounty that the pirates took a nice chunk out of their income, then they had seen my culture spreading and went into culture overdrive to force it back (which I had been slacking on). So between the pirates and culture defense and not knowing my layout they focused on stopping the pirates, which made sense since that had become their biggest problem.
Now I hadn't scouted too much either and well the cannons cheat, you can 'find' legal planets, but all you know is if they are dead or not, so I did a 3x shot vs their cannon world...no dice. Had to assume it was fortified.
I had been building SB and focusing on shielding, this helped but in hindsight the pirate raids helped more...it caused them to be the target else I would have lost a couple planets.
By end game we were pounding each other from across the system, but I was making holes he was just scratching. I noticed their cannon production went down (the in game economy ranking would switch between him and I for 1st so we were about even income wise)
And despite the fact I wasn't killing any planets the end-game graphs showed I put a big old hole in his income when I first started using 4+ cannons. By end-game I had 7 and had was sending out a Cap team to hunt down his cannons/culture/ and flagship.
Something I found helpful...let the cannons auto-shoot, just let them go, but try and stagger them. If I had a specific target I would check to see which was near reset and un-auto it (had a few hot-keyed). I always had a cannon that was almost ready for me to use manually. Was also one less thing to think about since they had some damn tough Starbases I had to fence with.
Off-topic rant: Also learned, I hate chasing flagships...and I hate minefields + AI. To often "stop" means make a wide 180 turn, and I have no idea why...turning off auto-attack, changing to hold position, and loose/tight formation all seemed to have no effect...they weren't bunched there wasn't an enemy that was too close...nothing I could see. Then other times they just stop and sit (pat on head).