I’ve been following and think it’s a bit simpler than that, he has a lot of big money donors who outright ask him to Take a pro Ukraine/pro Israel (tho to be honest all USA politicians are pro Israel except maybe Kanye), and you see him changing his stance a lot.
If he could have run a similar campaign to what he did for Florida governor Desantis would probably be fine but that isn’t realistic apparently. So we get the race we have
DeSantis' Jewish handlers are spending a lot of money for his campaign. By now, I think it's safe to say the campaign is not very cash-efficient as his polling is weak. He was supposed to be a serious contender against Trump and that is simply not panning out that way. People are not sold. Vivek on the other hand is evidently grooming himself to be Trump's VP by never criticizing him and appropriating many of his policies and rhetoric. I think this is a foolish move, but he believes that it will work for him in the long run.