The failure of the Chancellor's arrest by Mace and others who learned of Sidious' true identity led to the immediate execution of Order 66. This clone's covert operation execution protocol is swiftly carried out when it is realized that it has prevented the assassination of the Supreme Commander of the Republican Army.
It was a scenario devised by Sidious that the Jedi were in control of both sides, bogged down and prolonged, to create an elite class loyal to the Supreme Commander, the Honorable Chancellor, and to take over the powerful, united army by assassinating the Chancellor.
The truth was that the Jedi wanted to end the war by arresting the Chancellor, who was in control of the entire war as Sidious. This was countered on the pretext that the Chancellor was about to be assassinated, and the war was ended on the interpretation that it was a Jedi plot. In order to do so, the Jedi commanders scattered with their clones throughout the galaxy were quickly dealt with. The prolonged war made it easy to make the scenario make sense to the exhausted clone soldiers. Also, unaware of the truth revealed on Coruscant, the Jedi would never have imagined betraying themselves to their fellow clones.
However, there were more than a few Jedi besides Obi-Wan and Yoda who had miraculously escaped Order 66. Naturally, one has to wonder why they were betrayed. When they see the big news of the Republic's victory and reorganization on the holonet without being detected by the clones, they understand the scenario devised by Sidious about how the Council controlled the war in general. At the same time, they reveal their frustration with the Council for not ending the war. He mistakenly believes that the council is the dark side incarnate, having torn apart the moral values that the Jedi prided themselves on and catapulted a democracy they believed to be thriving into a military state. The emperor deceives them into believing that the narrative of a non-existent Sith Lord working behind the scenes with Count Dooku is unfounded and wrong.
Disappointed with the Light Side, the Jedi survivors will have to live in seclusion, hiding from the world, but they will not be used to having to endure the use of the Force.
After nearly strangling Mace and Yoda several times, Sidious decided to take advantage of the Jedi's inability to resist the use of the Force. He would use Lord Vader to flush them out and train them as Dark Jedi. A group of spies, called the Emperor's Hand, will hide from the world and help destroy half-imperial forces at home and abroad. As a reward, they are promised a position within the Empire. And so the game evolves into a competitive game for Vader's place. But Vader's position was not to be conceded until Luke Skywalker was discovered. There was no one else worthy of being Vader's successor except Luke. Translated with www.DeepL.com/Translator (free version)