The "best player on the best team" criteria was used to justify Steph's standing in the MVP ranking lists earlier on in the season (despite his long stretch of poor performances), therefore Book should be ahead of Jokic.
What MVP ranking lists are you talking about? There are none.
You cherry-picking what a few people said in the media wasn't the consensus of the voting panel. Narratives take a while to reflect what's happening at the time, so once it was clear that Steph was in a long drought and the Warriors lost the #1 seed, he was no longer the main name in the conversation. It started to switch to DeRozan, CP3, Bron, Giannis, Jokic, and the most prominent name of all - Embiid. Let's be honest here, this is all about you being mad because Steph was seen more as the MVP than KD was at the time. It's no coincidence you keep tracking back to referencing Steph. Narratives change all the time throughout a season. Just because you think it was "the best player on the best team" at one point, doesn't mean that's going to be the case later in the season, again, because there is no set criteria. Narratives change all the time, until they don't. The media might push a player at the start of the season because they're the best player on the best team, and then by the end of the season, the media is pushing a player because their team suffered multiple injuries and that player achieved some arbitrary box score stat mark.
Why isn't Booker ahead of Embiid and Giannis, who both have been mentioned in MVP conversations more than he has, despite being on inferior teams? Why make out like Jokic is the only one? Why do you believe Booker is the one deserving of being the MVP, when prior to CP3's injury, he was seen as the Suns' main guy? CP3 finished 5th in voting last season, so what has changed where Booker has now replaced him in that frame, where they aren't taking votes off one another?
The voters don't just get to randomly flip the voting guidelines that they set earlier on in the season to place someone else in pole position. Book's MVP candidacy is just as valid as Steph's was earlier on in the season.
There was no guidelines. And who are these voters you're talking about?
If Booker didn't have CP3 on his team where he was seen as the definitive #1 guy, then he probably would be getting more attention, but since CP3 was the face of the MVP narrative (on the Suns), Booker couldn't possibly be that guy that Steph is for the Warriors. How can you not see something so obvious? Its the reason why, again, all of Jokic, Embiid and Giannis are in the conversation more than Booker is, despite being on teams with weaker records.