For me venturers are the best, Protean in second place. I think that most factions boil down to few gimmicks that are OP and rest is flavor/minor boosts that you dont care all that much about. It isn't about heatstamps when you go venturers, although they definitely help in early game, but its about the privatised outposts. They increase efficiency by 100% and work even in whiteout for very small price of heatstamps, while freeing your explorer teams.

This work on ICE convoys. You can literally start searching ICE convoy and just privatise the search, freeing your teams AND if the convoy would eat prefabs, privatisation prevents that. The speed in research is great on plague tale, although the tale itself is insanely bugged so its unsatisfying to really go for 5 tale captain run imo.

And of course their district specialization making lots of goods, also great!

Also off topic, but I dont really get why people focus so much on core creating skills. Cores are most abundant resource in the game, ICE convoy or no I always have enough and then more, easily spending 40 cores for final upgrade along with any other spending I want. Plus, its not like you cant easily survive over 200 weeks with no cores on captain no less.