Change default math font in Powerpoint

The default math font for MS Powerpoint 2016 is "Cambria Math". In some cases, I want to change it (e.q. "XITS Math").

I found a solution for MS Word (Select a different math font in Microsoft Word). However, it cannot apply for Powerpoint because the Equation Option dialog in Powerpoint differs from the one in Word.

Here is Equation Options dialog in Powerpoint:

Here is Equation Options dialog in Word:

How to show the full options dialog for Powerpoint like in Word?

According to this post, Cambria Math is currently the only supported font. The user on that post recommends selecting your equation after you have finished, click on the Normal Text option to turn it to plain text, and then apply your desired font.