I'm gonna give my thoughts on this to get the match started. I believe that Obito is definitely superior to either fighter individually, although I don't think it's by a massive margin. The reason I think this is that there's a preponderance of narrative implications for Naruto needing KCM to beat Obito.
And DF Sasuke was stated to be equal with FKS Naruto (this doesn't mean base to base, since in their Rasengan Chidori clash, they did their weird mind talk thing and could see each other's true selves and strengths).
As for why I don't think it's a massive difference is because it was stated Sasuke surpassed Alive Itachi as soon as he transplanted the EMS.
And there's quite a bit of evidence suggesting Itachi>Obito.
(Note Obito specifically recognizing Itachi as an opponent, then he directly stated himself that no "opponent" was worthy of Itachi)
So initial EMS Sasuke>Alive Itachi>OM Obito~>/>DF Sasuke. I know the EMS is a big boost, but the hatred amps and training are what really made EMS Sasuke SO much stronger than MS Sasuke, I don't think just transplating the eyes is like an exponential massive boost, so MS Sasuke should be somewhat in the realm of EMS Sasuke and by extension OM Obito.
At best, I could see Obito being like 1.5x stronger than Sasuke/Naruto individually, but with them as a team they should be able to overwhelm him. How will they deal with Kamui you ask? Well, he has to materialize to attack, and he's not gonna catch one of them slipping without the other noticing and intervening. Shadow clones could help a lot. He'll eventually get overwhelmed and tagged by a Rasenshuriken or Susanoo Arrow or Amaterasu. Izanagi could help, but then they could take him down again. Maybe he could outlast them because SM has a timer and the MS is very draining, but I still think they'd take it more times than not.