For me It is inferred that the federation is even matched to KE, or RSE. Like the US, China and Russia in the 60’s and 70’s ( China and Russia were not bosom buddies)
These Empires subjugate their member worlds, so their “colonies” could really be a pre warp world that happen to have large deposits of Dilithium, good farm lands ( why farm when you can replicate) and now is a “part” of the Empire.
Without silly rules and directives they could go to these worlds where the Federation would say we’ll wait a few hundred years until they get warp to warp 1. This could give the KE and RSE a lot of worlds and resources for the war machine, but not the personnel to man the mines and till the fields so they would keep the locals as cheap labor, periodic visits to pick up the resources, kill a few locals if the quotas are down, etc.
In worlds of strategic value (good anchorage and such) kill the locals build up the planet and scare the federation