Endless Legend is designed to be more of the "fantasy" equivalent to the Endless Space franchise. While it is technically a sci-fi game with futuristic tech, the empires you play as are mostly primitve compared to Endless Space because they are still confined to the planet as opposed to the space traveling empires in Endless Space. There of course some exceptions.

The Kin of Sheredyn are an offshoot faction of the United Empire anbd therefor have access to more advanced tech. That's reflected in their buildings that all look high tech. They also have access to satellites that can fire orbital lasers at targets. Besides that however they stick to archers and swords for some reason, even their giant robots use swords.

The Last Lords are the remaining Broken Lords from Endless Legends that escaped the dying planet. They are technically digitalized consciousnesses in knight armors. As far as other factiosn go, this is pretty advanced but at the same type they love their knight aesthetic a bit too much which is why they don't use guns.

Necrophagfes are... well bugs, all their "tech" is organic and they cannot space travel. They are just seeded on multiple different worlds and adapt to their environment which is why the Necrophages in EL2 play so vastly different to their EL1 counterpart.

Tahuks technically have the most advanced techs. They were techaed by the Endless directly and are interested in advancing their knowledge further in hopes that will bring back the Endless some day. They have hoiverboards, energy weapons and war machines.

Aspects are corals with robot bodies. They use robot units but still use archers for ranged weaponry whioch might be simply because they were inspired by ancient asian culture.