Vader was out of control, and it was a bad look. So, Palpatine tasked Mas Amedda with tracking Vader, but not to rescue him. The evil Emperor wanted Vader dead. While Vader tasked Doctor Aphra with finding a way to control his powers, bounty hunters attacked them.
Return of the Jedi, however, proved that Palpatine had a significant blind spot. There were plenty of warning signs Palpatine could have heeded that Vader might turn on him, and yet his ignorance and arrogance led to his decisive downfall.
The short answer is yes, without a doubt, Vader regretted becoming a cybernetic monstrosity. First, there's the constant pain and discomfort from his suit. Worse, however, is the psychological pain. Vader destroyed everything he had ever known for a chance to save Padme.
After Darth Vader refused to kill both Luke Skywalker and Padmé's body double, Sabé (which would've threatened his manipulation of him), Palpatine punished him by attacking him with Force Lightning.
The HORRIFYING Surgery Anakin Went through to become Vader! (Star Wars Explained)
Did Sidious want Anakin to surpass him?
Sidious always said that Anakin—well Vader—would become more powerful than him and anyone in the galaxy. He said this to Yoda prior to their duel and he continued to say it.
Darth Vader Hated Palpatine More Than Even The Jedi
For all the hate he directed upon himself, he'd come to hate his master just as much if not more, especially after learning that Palpatine had kept the truth about Padmé's death from him for so many years with the reveal that Luke Skywalker was his son.
Even in the old Star Wars canon, the two had a confrontation, as they met in the comic book Star Wars Tales #9, where Maul pieced together that Anakin was Vader.
The novel explained that, had Vader killed Obi-Wan on Mustafar, he would have tried to kill Palpatine too, but given how badly wounded he was after the duel, his power wasn't the same and he was weak, both physically and mentally.
As Darth Vader, he was one of the strongest beings in the entire galaxy. But even then, he was never able to surpass his master, Darth Sidious. A Sith Apprentice can only become the master when they murder the one who trained them.
Vader had lived most his life with Palpatine. He probably thought of him as a father figure. They were in constant contact with each other and planned and plotted every action to secure power. 90% of the time they got their way.
No, Darth Sidious did not respect Darth Vader. Not likely he feared him but saw his value as a puppet. IMO he respected Sidious's power… I don't think he respected him as a person due to the fact that Palpatine was a narcissistic liar…
For his disobedience, the Emperor punished Vader and resolved to teach him a lesson in the dark side of the Force, removing his cybernetic limbs and having him dumped on Mustafar by a squad of death troopers to either strengthen his Sith apprentice with pain or leave him for dead.
Vader knew that he could never defeat Palpatine by himself (especially after his master bested him on Exegol as well), which is why he tried to recruit Luke to help overthrow him during the Empire Strikes Back. He may have not been able to overthrow the Emperor, but he could throw him over the railing to save his son.
As the Chosen One in his prime, it's quite possible that Anakin would have had a strong chance of defeating Palpatine aka Dark Sidious. Palpatine himself told Yoda before their Revenge of the Sith duel on Coruscant that Darth Vader would become more powerful than either of them as he continued to grow in the dark side.
Up to Star Wars: Episode VI - Return of the Jedi, Palpatine treats Vader poorly, and they very much have an abusive relationship. Darth Vader hates Palpatine yet is eager to please him, whereas Palpatine goes back and forth between acting as a friend and showing his hatred.
Palpatine met Anakin Skywalker shortly after the Battle of Naboo, where he would "Watch [Anakin]'s career with great interest." Following this, Palpatine has poised himself as an understanding figure towards Anakin, who also felt Palpatine was the father he never had, especially since the Supreme Chancellor seemed to ...
With that being said, if Palpatine did, indeed, use Force-healing to keep Vader alive, he didn't appear to have given enough life force for it to take a toll on him -- and being as close as Vader was to death, Palpatine would have required a lot of energy to keep him alive.
