Thing about the Vex is, if a Mind decides that the most logical course to ensure their survival is to ally with humanity, they'll do it. They've displayed the willingness to cooperate with Guardians during the Taken War, when all simulated futures that didn't involve cooperation resulted in their extinction. That being said, Vex can never be fully trusted, as things like loyalty and integrity are irrelevant to them. If they establish friendly relations with Guardians then calculate that betraying them would result in a more favourable outcome, they will pursue it. The only true way to remain allied with the Vex is through deterrence and favourable outcomes from maintaining the alliance.

If I am right, the vex are a non sided faction, not in it for the light or dark, the only vex that is part of the dark is the sol kind, as even in lore the normal vex stay away from the sol type, the ones we find in the black garden and garden of salvation and now spire But there were vex who were not the enemy, when the taken attacked the vault of glass, or that friendly harpy we found on Nessus And the last time the vex was a threat and not taken over by the witness or the part of the sol, was panoplies back in curse of Osiris

Right….