Sidious gets owned by ROTS Mace and ROTS Anakin together starting at a short distance.
At a larger distance he could probably choke out Anakin and Kenobi pretty quickly leaving it as Mace vs Sidious again which we've seen can go either way when Sidious has already expended some energy at the beginning of the fight, and given Mace the opportunity to turn the fight into close quarter combat.
what does small distance mean? Like B team in his office? Sidious might be able to dispatch Kenobi in the first 30 seconds if he wants; otherwise both Mace and Anakin are pretty solid together though not impossible to beat in pure sabers. I only saw Mace winning his fight because of the amp, without it he's not performing on the same level.
If Sidious has two sabers he wins 7-8/10
If one saber he might be able to blitz Kenobi;
Both Mace and Anakin rely on a strong offense more than a defense and I could see Sidious exploiting this. Assuming neither Anakin or Mace take some kind of amp, Sidious wins 7/10