And to add: It's like this:
WWE likely will have more money, and some more "First time" matches and a potential CHAOS reunion/feud with him and Nakamura, but also creatively isn't a guarantee since WWE is more promo reliant of the big two and even with a different creative force than what was around when Nakamura was in the main event the first time and was hurt to a point it took years to repair to the point he was near where he was, it's still more of an adjustment. Also WWE even to this day is still unlikely to draw on his NJPW history.
For AEW, there's more familiar names, still likely will be paid well, and even if it is still "familiar territory" in regards to more crossover of familiar names, they'll still treat him like Okada and will probably be instantly slotted in the main event and needs less "introduction" to the fans. But obviously AEW likely won't have as deep pockets as WWE and AEW isn't as much in terms of exposure.
And of course, both companies have fairly stacked rosters in terms of numbers and talent. So that argument is a "hurdle" either way. No matter what happens, it is going to be an interesting next month or two and Okada would be an asset to either company and to treat him as anything but a major international star would be a disservice to him.