If that's the case (and I think you're right: Tokon coming to Xbox), then SIE should've announced it at the reveal. This is what I mean by the confused messaging: they want to have that "hype moment" with the fanbase by pretending to give them a big quality AAA 3P exclusive with a mega-popular IP. Marvel, no less, knowing many people (including Xbox gamers) will see it as a spiritual successor to the Capcom MvC games, and knowing Xbox gamers will feel left ou, creating cries of port-begging which just generates more attention.
Yet....part of the hype would be fake since SIE would know Xbox was a planned platform from the get-go. So it makes all of that feel manipulative. And yes, I know a big part of marketing is to manipulate the perception of customers by tugging on emotions, but I'd feel a move like this with Tokon is manipulative on another level. The type where corporate greed for profits wants to hide behind language of an era when companies like SIE used to actually care about being competitive with genuine exclusivity. So now it's not just customer emotions getting manipulated, but also their wallets.
There's no point in withholding a Tokon Xbox announcement other than to manipulate preorder traffic to your own console (which makes less sense here because the game's Day 1 on Steam anyway, and a lot of the FGC prefer that and PC as a platform), and play off historical fan culture in gaming spaces. You can argue that any Xbox audience that'd be interested in the game would simply get it on PS5 or PC, but then the mere fact of porting Tokon to Xbox is a contradiction: the audience you'd be selling it to, would have already opted for PS5 or PC by the time you made the announcement!
All that said, such logical thinking didn't stop Helldivers 2 getting an Xbox version 18 months later, so I guess SIE feel there are many holdouts still on Xbox no matter what. Which in their eyes probably makes a Marvel Tokon Xbox announcement some months after reveal, make more sense. I just personally don't see the value in withholding that announcement at this point if you know you're gonna release the game over there anyway, other than to score temporary brownie points and roleplay a console exclusivity strategy you aren't actually committed to in practice.