In a huge interview article with GQ, Druckmann explains that, so close to the release of The Last of Us Part II, his thoughts have inevitably begun turning to the next project: "As you start wrapping things up, creatively there are fewer and fewer responsibilities and my mind can't help but think about the next thing. So yeah, the next thing could be a Part III, the next thing could be some new IP."
Druckmann gives no indication as to which he prefers, with GQ paraphrasing his mindset as, "Ultimately, the best idea wins."
As if to reinforce the idea that any Last of Us sequel will focus on the same kinds of locations and characters, Druckmann adds that, if you were to wildly change setting or protagonists, "To me, at that point, you might as well just do a new IP."
IGN article is here which includes a poll where the majority would prefer a new IP:
https://www.ign.com/articles/last-of-us-part-3-sequel-naughty-dog-new-ip
You can read the full GQ interview here:
https://www.gq-magazine.co.uk/culture/article/the-last-of-us-part-ii-neil-druckmann-interview