Out of those three, Impact would be the best move.
-The NWA would be a very short term option. Outside of wrestling Aldis, why go there. He would either job and leave, or split a series before jobbing out. I lost track of NWA since they came back
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-NJPW would be dope. I can see him as a lone wolf going as BC and pretty much being a bad ass talking shyt. Would produce the best matches for his style. However, with his medical issues, I don't know if he wants to wrestle strong style and then fly all the way back to the states after every tour, especially given the fact that you can't fly if you suffered a concussion.
-Impact: After Mox causes Omega to lose the title to Moose at Slamerversary, I can see Joe coming out to challenge Moose for the title. He can have some good matches with Moose, Swann, Edwards, etc. It'll also give him a chance get back into wrestling shape and make sure he's good to go before signing with AEW or NJPW. If I was Tony Khan, I would advise him to sign with Impact for 6 months-1 year to make sure he's good to go. Bring him in through the "forbidden door" for a quick feud before signing him to an actual contract.