I get your drift - currently it looks as though it is a 2 horse race. In which case, if so, I anticipate ND to put up a formidable challenge and CA to do likewise. I too believe that these 2 are the favourites as things stand. I suggest that we'll have a better opportunity to assess after Toronto/Cincinnati.
But Destiny and Lady Luck have not, as far as I know, given guarantees that one of CA or ND will win the USO. All participants with an eye to the title will want to play their best tennis and win the title. It is the stuff of dreams, and aspirations take flight when a player can play to their strengths.
I remain optimistic that CA's younger rivals, including Rune / Sinner and excellent players on recent good form such as Medvedev (there are others too) will put up good challenges, and make it an interesting tournament. If not, it is a wonderful prospect to have CA / ND in the final at the USO 2023 and I for one will not complain.