Clone Army Origin Tips
Do your archeology site as soon as you can and become an ascended clone, optimize your starting build order so you can have supremacy complete and your entire fleet cap filled up before 2220, find your first neighbor, create a defensive station between you with the module to reduce disengagement chance, declare war, let them come, destroy their fleet at the station, march forward and take their capital.
Use their main species as a replacement for your own, but only ever allow OP clones to be leader, colonize other worlds and fill them up with the one species you’re treating well, the rest can have lower rights/slavery.
After that try to aim for the psy ascension, a clone admiral by itself has enough bonuses to beat genocidal empire fleets, just from the ascended clone trait, throw in psionic bonuses as well and nothing in the galaxy will be as strong as your fleets, while you’ll still be able to retain full diplomacy rights, federation bonuses, vassal bonuses, and most importantly the option to join the galactic community and delay the vote to turn you into a crisis forever.
Also, yeah, genocidal clone army is kind of eh… Can be fun for roleplaying purposes, but you’d either have to abandon the OP bonuses from being an ascended clone, or just live with a pitifully small population that won’t be competitive even before the midgame, plus all the limitations to genocidal empires and most importantly the fact that even if you win a war, you can’t ever win anything as you can never conquer pops, the most important resource in stellaris, personally I’d never consider taking any kind of genocidal other than RP, they are really, really weak.
So sub-optimal but fun build i like is Fanatic Purifier / Distinguished Admiralty Clone Army with Militarist / Fanatic Xenophobe Ethics.
You get significant early game advantage from getting 100 pops almost immediately + solid fleet buffs, success or failure depends on how quickly you can overwhelm a neighbour or two and purge their planets which will produce tons of Minerals / Food / Unity
If you take the clone ascension dilemma path the only way to get pop growth will be through building robots / synths, the Cybernetic and Genetic ascension paths won’t be of any use, you can take Synthetic Ascension but will lose the clone traits so unfortunately Psionic will still be the most useful path.
Playing Clone Army with purifier is indeed suboptimal.
Best way is Spiritualist/ Anything. Key civic is the “Sacrifice Population for Happiness” civic, which gives you an edict where you can sacrifice pops for 50-60% extra happiness depending on how many sacrificial temples that you build.
Conquer other pops ASAP and build research labs on their worlds, but build sacrificial temples on your Clone planets for max happiness.