And this pop system is so dumb. It would make so much more sense having to deal with overpopulation because the more people you have the bigger the population growth.
It's a dumb system stapled ontop of another dumb system to patch up the hole in one while creating others. Nothing about realism or fun gameplay justifies the growth system, the growth system is justified on the basis that the devs simultaneously can't optimize their own game while also being unable to admit that all of their work into the economic system has improved nothing and merely killed performance and the AIs ability to handle things.
Most powerful now is lithoid hivemind with terravore trait and calamitic birth origin , when you use the (cheap) colonize option by meteor you create blockers on the new planets, you then spam it everywhere . Clear blockers you get extra pops , consume the planets you get a bit of eveyrting , keep a few central well defended good planets, consume everything. When the planets break , all the pop are automatically relocated . So what was a weaker build turns out a godly build completely bypassing pop troubles. Then of course you spec them for mineral and they have volatile mole traits , to help clearing blockers faster
You now have an economy with colosal mineral production and stock, spam the menace ships they only cost minerals, dont even give a fuck about their fits, you will crush eveyrone under the sheer mass.Huge empty space area so they will never reach your core system . Oh and devouring planets even raise your menace score, star eaters are beasts ...
Doesn't that completely screw you in terms of long term pop growth, since you are both destroying pop creation centers (planets) while also unable to assimilate pops from things you conquer?
Think the best build is still some kind of slavery regular empire with Technocracy, which gives you super-scientists as rulers on each planet. This combos well with having lots of low pop worlds (which is inevitable now) and you can still whip all the planets you conquer into the mines to give you more research and alloys.
Also the most powerful build in general, including origin selection, is definitely still anything with Hegemony. Because this way you can abuse the AI's ability to make 100s of corvettes even while on one planet while also abusing the fact that as a player you can order them around competently and conquer the galaxy. You can literally build no fleets as a Hegemonic start if you want and the AIs will still build a federation fleet strong enough for you to conquer other AIs. All you have to do is pick up the one perk that causes your naval capacity to count +100% towards the federation and then spam starbases for more naval cap.