As I've stated before, Maul has, in the past, shown that he is willing to kill Sidious when given the right reason.
Willing to kill is not enough to guaranty best performance. Emotions can be conflicting regardless. It is clear that Maul feared Sidious. On the other hand he never feared fighting Jedi.
And no, Maul can not almost best Sidious on his own. As I said before, their first fight was a test by Sidious, which was written through Maul's perspective.
You can't really say things like that. You are right that it was from Maul's perspective. Yet, at the same time we
don't know Sidious' perspective and he would never admit to Plaguies that he nearly got killed as it would make him unworthy of apprenticeship to Plaguieis.
In other words there is no real answer to how close Maul got to killing him.
What I can say is that prior to the fight Maul was stranded on that planet for a month and undergone a lot of suffering. There is every reason to assume that his rage reached its epos, so it is fair to assume that he gave Sidious at least relatively hard time.
Anakin on getting enraged overpowered Dooku, similarly inferior Luke overpowered Vader.
Emotions play very important part in performance.
Ventress on getting enraged fought both Kenobi and Anakin simultaniously, kicked Kenobi so hard that he collapsed and it took him time to recover and ultimately Force choked them simultaniously.
Similarly Opress on getting enraged choked Dooku and Ventress, threw Kenobi and Anakin across a corridor and gave out Force wave slamming everything in its wake. Both Ventress and Opress never showed similar performance after because you can't summon rage at a whim.
Sidious toyed Luke in first fight, yet, in second fight Luke not only matched his speed but outskilled as well, such a huge difference can be because of emotions.
In fact, in the Plagueis novel, Sidious tells Plagueis that he allows Maul to believe that he is more skilled than he actually is.
And? Regardless both of them praized him.
Sidious:
" He's even more formidable against living beings.
...
I stranded him on Hypori for a month without food and with only a horde of assassin droids for company. Then I returned to goad and challenge him. All things considered, he fought well, even after I deprived him of his lightsaber."
Plagueis:
"The Zabrak's fists and legs were as lethal as his lightsaber, and his speed was astounding."
If Sidious could really blitz Maul, it would make no sence why he was impressed with him and why Plaguieis was specificaly astounded by his speed.
In any case you both agreed that Maul is faster than those three Masters. However, it is imposible to make even relative estimates of how fast he is between the Masters and Sidious.
For example, Anakin had 10 years of proper Jedi training with thousands hours of sparring with Kenobi and plenty of real fights. Yet, his speed was equal to Kenobi, Dooku and Ventress - all three with inferior power comparing to him.
In comparison Luke who is at most as powerful as Anakin after 11 years of training most of which was self thought matched speed of Sidious.
Also, I don't get why both of you despise ABC logic so much. It works in determining relative power, strength and speed. The rest depengds as I said above on emotions and, also, on other circumstances.
For example, Dooku's style lacked kinetic energy and he had to outmaneuver instead. But when Opress attacked him, he was forced to block directly because there was crumped space and he was distracted by Ventress, thus got disarmed and overpowered by unsuitable circumstances.
In RotS novel Sidious had fear of falling out of window and redirected some of his power to prevent that and Windu took advantage of that and as result defeated him.
Anakin in film defeated Dooku with surprice grappling technique. And so on.
Both Maul and Opress are in speed league of Kenobi, Anakin, Ventress and Dooku. And Dooku wasn't even overwhelmed by Yoda's speed. So I say Sidious can't blitz either of them.
At the same time it is still possible for Sidious to defeat them nearly instantly but he would do it by outskilling and overpowering them, not by speed blitzing.