There is a little dilemma you are in, because the Tempest and the AR are at least supposed to do similar things. But be cautious to sell one of them, it might be just the wrong decision. If you are not short of money, put the one you are not in to right now on the shelf.
I would recommend, go with your feelings. All three boxes are musical instruments, after all. The one you like most, will give you the most. Focus on that one and learn at least the basics fluidly. Then carry on.
You can also use all three together. The OT is a nice little mixer too and can be used to work on sounds from external audio sources (see Thru or Neighbor Machines). You can connect your AR and the Tempest to the OT and integrate the various features of the OT step by step. You could also use the Tempest as your melodic synth, because it is not as specialised to percussive sound generation as the AR might be and use the AR as your drummer.
There are many options to connect and use your “Trinity”.