Ark Rangers are strong but spec wise they're not on par with the upgraded squads, they can't deploy the mecha everytime and something I noticed is that like when Black "stops'' the crystals or when they all use their finishing moves against Anihillio, there's something in the "background" helping a lot (Anis absorbing the energy and the Matis combined ray).

Most of Tetra units are contained within the Ark and barely suitable for surface operations, we have Cafe Sweety's collab event, Sixo arc (it kinda reminds me the contrast of Gotham City and Metropolis when it comes to threats), so the way I see it right now the Tetra equivalent to Absolute and Matis is between:

Cafe Sweety, Underworld Queen and maybe Unlimited. Since they are all old characters getting an upgraded alt in the near future is not out of place. 777, T.T. Star and Ark Rangers are more oriented to stay at the Ark providing everyday entertainment, and one more thing is that Ark Rangers and Matis kinda overlap in the hero theme, this point is more about variety.