Originally posted by Darth Thor
Interesting. I would think he would have his hands full with just Maul and Vos. Having Dooku plus just one of the others is probably plenty. All 3 I would think is overkill.
Vader might be arguably more powerful overall than ROTS Palpatine or Yoda. In that im not sure either of them could take out a Rebel fleet like Vader does in Rebels. But it seems the suit somewhat restricts him in a Lightsaber duel in canon same as in Legends. His TK would be too much for any of them to deal with in a 1 v 1, but two of them will be all over him for that to be an issue methinks.
I know Vader is at his peak in the ROTJ era, but I am considering his one v one fights against Ahsoka, Kenobi and Cere tbh.
I consider Vos and Dooku to be roughly on par, given what happened in Dark Disciple. They're both in the same general tier as RotS Kenobi. So the way I see it, Maul+Vos math out to about the same threat level as Maul+Dooku. So you and I are aligned in our thinking that all 3 would be overkill.
As for whether or not Yoda and Palpatine could take out a small Rebel fleet like Vader did in Rebels (and replicated at the start of the Vader Down comic), it's kinda hard to say. Neither Yoda nor Palpatine have any real piloting feats to their name, and piloting is a skill that needs actively developed, just like lightsaber training. Just because they might not be able to pull off the same piloting feats as Vader doesn't necessarily mean they're less powerful than him. Just that he has far, far, far more practice than either in a cockpit.
When you look at other metrics that are more easily comparable, like army busting feats, Vader's performance tends to be on the scale of Yoda and, by extension, RotS Palpatine (Vader fighting the Rebel army in Vader Down being similar in performance to Yoda fighting the CIS attack force in Ambush, for example).
Regarding Vader's suit restricting him in Canon, I'd say it's more fair to call it a trade off. Yes, Vader in the suit is not as agile as he had been as Anakin (allowing Obi-Wan and Ahsoka to reliably outmaneuver him), but his improved resilience, stamina, and strength, coupled with his retooled fighting style, seem to more than make up the difference. The first half of his final duel in the Kenobi series is proof enough of this. Obi-Wan was fighting on the level of his RotS self, but Vader seemed to still be roughly evenly matched with Obi-Wan, possibly holding a slight edge (he threw Obi-Wan around early in the duel, landed a clean pommel strike on Obi-Wan's face after the "your weakness remains" scene, and in general appeared to tire less quickly than Obi-Wan, who seemed to be gassing out by that point in the duel while Vader still seemed fresh).
Looking at his fights against Cere, Kenobi, and Ahsoka is fine as a measuring stick for those time periods, but really don't tell the full picture of his development. His fight against Cere seems to have happened before his fight against Kenobi, and the Kenobi fight spurred enormous growth for Vader afterward ("When I left you, I was but the learner. Now I am the master"

. We know for a fact that Old Ben is far greater than 10 BBY Ben in Canon (after the Kenobi series he began his training under Qui-Gon's spirit, implying substantial spiritual growth, which equates to a meaningful increase in Force power), and in From a Certain Point of View, we see that from Old Ben's perspective, he was hopelessly outmatched by Vader during their ANH duel, demonstrating just how much Vader had grown. Then post-ANH he grows even stronger thanks to the discovery of his son, and his struggles against Cylo's creations. Post-ESB, his growth skyrockets as he starts making repeated attempts on Palpatine's life, at a point in time when Palpatine had basically become a living eldritch abomination.
Vader's best dueling feat, and probably the best measuring stick we have for him, came from Hidden Empire #4, where he had a sparring match against Palpatine in 3 ABY. This match is almost a panel-for-panel runback of their first sparring match immediately after he built his first lightsaber in 19 BBY, in Star Wars (2020) #25. 19 BBY Vader was helplessly, utterly outmatched by RotS Palpatine. We know Palpatine grew tremendously after that due to his access to the Sith temple below the Jedi temple, his access to vast stores of Jedi and Sith artifacts plundered from the Jedi temple (such as Momin's mask), his ventures into the Unknown Regions, rediscovering Exegol (something he was implied to have started looking for around the start of the Empire's reign), and feeding on the collective suffering of all the people in the Galaxy under the Empire's rule.
Despite all this insanely massive growth, when Vader and Palpatine had their rematch in 3 ABY, Vader's performance against Palpatine was significantly better, basically matching his master blow-for-blow. This implies that Vader's rate of growth actually outpaced Palpatine's own rate of growth, with Vader beginning to close the gap between himself and his master despite Palpatine having far, far more resources through which to build his power (It is worth noting Palpatine thought he might be rusty due to lack of lightsaber training at this time, which is what spurred the training session to begin with, so 3 ABY Palpatine might be slightly less skilled as a duelist than 19 BBY Palpatine. This is likely offset by his enormous power growth though, so I still count it).
All of that being said, in terms of dueling ability, I'd lay it out like this:
Ahsoka/Cere/Maul<10 BBY Kenobi/RotS Kenobi/Quinlan Vos< 10 BBY Vader/RotS Anakin/Dooku<Enlightened 10 BBY Kenobi<Old Ben<ANH Vader<Yoda/RotS Sidious<ESB Vader<RotJ Vader<RotJ Sidious
Or, simplified to just the combatants in this match up:
Maul<Quinlan Vos<Dooku<<<<<<RotJ Vader
Now, this looks like a massive stomp in Vader's favor, but honestly each "<" represents a relatively small gap in ability, due to the nature of diminishing returns, and the fact that all of these characters are basically on the highest end of dueling ability in the franchise. Vader is definitely far better than any of his adversaries here 1 on 1, but the moment he is having to face multiple Kenobi-level threats at once, he's in danger. This would be like throwing RotS Anakin, RotS Kenobi, and Seige of Mandalore Ahsoka at RotS Palpatine. It's theoretically possible for the more powerful single combatant to come out on top, especially when factoring in Force spam, but the team has the more favorable chances.