So I decided to try a One Planet play through on insane because I'm into masochism. It was so god damn much easier than a normal play through, even though the risk of being steamed rolled in one early war was still there.
In my normal play throughs I almost always have to submit to vassalage to one of my neighbours.
This time with only one world and zero border friction negativity from my neighbours, I managed to buy their intital crappy reaction off with one sided mineral exchanges, food, research agreements and star charts.
After 10 years or so the initial 'first encounter' penalty is gone and you start to earn the 'trust' bonus. From there it is equal trading of minerals for energy (essential, as I was always negative energy PT) and research agreements all game.
By 2275 I had all of my tech for Battleships, had Void Borne and Galactic Power and was rushing out Megastructures very soon after that, so I decided to colonise a near by 25 tile planet.
So I ruined my 'one planet' run, but ended up even stronger because of it. The negative % from two planets is not particularly more painful than from one planet, and I managed to start getting mineral and more unity production (habitats provide gold and science).
By 2300 I had Megastructures and started building my Ring World (a HUGE mistake, that thing was a complete waste of minerals). After realising this I had colonised 13 systems within 10 years.
By 2320 I swapped from Fanatical Pacifist and conquered the nearest Fallen Empire. I am now at 2339 and am only researching repeating technologies and fighting off an Awakened Empire and striking at my neighbours during a truce.
The worst part about this game is that I can only get ~20 FPS during normal gameplay and ~10 during space battles.
It really sucks, despite only ~30-50% of my CPU and RAM being used at the time. This is one of the most poorly optimised games I have every played.