No, they are not billionaire funded. It is more likely to be a result of PragerU their lawsuit against youtube and YouTube adjusting their algorithm to give them a bit of a boost
I'm not sure if Ben Shapiro is being directly funded but it looks like PragerU is mostly funded either directly by billionairs or by think tanks (which are often also funded by billionaires but I don't have time to dig into all of the different ones mentioned here)