It's way more than one billionaire, transphobia has substantial financial backing from basically every big fund for reactionary causes, from the Heritage foundation to Citizen Go or TFP (at this level, the Venn diagram between transphobia, homophobia and antifeminism is also basically a circle, actual TERFs in the historic sense of the term or transphobic cis gays only show up much further down the food chain). Many of the financers are individual billionaires like Rowling, Mercer or Malofeyev, but they also do more spread-out fundraising, Citizen Go being the prime example for that.

But yes, fascism is fully backed by capital, and that includes every fragment of reactionary ideology.