For how much people meme the fanatic purifier path in Stellaris it really is clunky as fuck
>meet new xenos as as total xeno death empire
>can dick around and blow up their fleets and not much more until you finish first contact
>if you're anywhere in their territority they close borders instantly and your fleet goes MIA
>best reaction for running into unidentified aliens as the alien killer empire? basically ignore them until first contact is done so you can prepare a genocidal war in the proper way like a real gentleman

>conquer one of their planets
>it's a horrible piece of shit with awful habitability and seemingly randomly picked buildings
>my own pops go there before the purge of the aliens is even finished
>have to resettle them for energy and unity
>abandoning a planet costs 200 Influence because FUCK YOU
>turning off free internal migration isn't really an option because the new colonies I actually want heavily require migration to grow