Ajax IFV is not Ares, it is based on a lengthened Ares hull, but the interior and turret etc are completely different. And Blackjax is yet another different vehicle, basically a testbed recce Ajax used to trial integration of things like Iron Fist APS.
Seeing as it seems to be a point of confusion (which is understandable, all these vehicles are extremely new and have only been shown in public a handful of times), Ajax IFV is not Blackjax, nor is it Ares. They are all distinct vehicles.
Ajax IFV is a newly revealed IFV variant of the Ajax family, utilising an unmanned turret, a full size troop compartment with 8 dismounts (unlike the measly 3 dismounts that Ares can carry), Iron Fist APS, and Javelin FnF ATGMs.
Blackjax is a standard Ajax reconnaissance variant (so a manned turret, no troop compartment, no ATGMs) which is being used as a testbed/demonstrator vehicle for new technology integration, like new sensors as well as also trialing Iron Fist.