I see Foden and/or Grealish shifting to those positions over the next season or two. Also depends how we see Mcatee and Lavia progressing over the next couple of seasons too. I think if Sterling goes his place taken by a striker.
I see the attraction of De Jong, not sure the club will see him as a priority.
I can see a situation where we agree a loan deal with Barcelona for Sterling, with a fee to be paid in the summer, once their finalised financials have allowed them to take into account this season's resumed stadium attendance income, which will raise their spending cap.
If they are still in a position they can't meet the price, we get DeJong in instead in the summer maybe.
As you say, no real need or priority for him at the moment. Squad spaces are not an issue, but where he fits may be.
Unless the club are willing to get him in early and suck it and see for the rest of the season to secure the player long term, with dinho and gundo coming to the end of their contracts. Bringing both him and a striker in january feels somewhat unlikely imo. And if Sterling left, you'd like to think the priority would be a striker into the team.