If Sidious did something to anger Vader, for example maybe he kills Padme in front of him, do you think Vader would be able to defeat him? Would something like that awaken his full potential so that he’d be able to kill Sidious?
I guess this pretty much happened already in RoTJ when Palpatine was going to kill Luke, but that wasn’t a true fight.
Vader already raged out in ROTS when Palpatine told him Padme was dead and he couldn't even touch him with the Force; everything else in the room got crushed and Sidious just stood there smiling. The novel goes even further saying that Vader reached out to kill him with the Force but didn't have the strength to
Not to mention that the novel is practically retconed by the comics where we see Vader tk slamming Palpatine into a wall right after he got off the operating table.
^Vader is also trying and failing to Force Choke Sidious there. But yeah anyone who kills Padme in front of any form of Vader/Anakin is getting dusted imo