I work in the landing page editor frequently and today I don’t see the option to select the font from the builder.
I chatted with support and called support and both referred me to the settings where you can define the default font styles, and neither rep had any idea what I was talking about. Thank goodness I found the article here that allowed me to see a screenshot of where the font style has been otherwise I might have thought I was going mad: Landing Pages - Text editor toolbar | Max Classic