How can I export a note + its text to a PowerPoint presentation?
There is no automatic method to generate a PowerPoint file.
But you can export formats that can be used to generate a PPT/PPTX. For instance, export HTML and go via pandoc: this suggests it is possible. Or, directly generate the MS Office XML for a PPTX, for which you’d need to created some approariate export templates.
You can do this using Pandoc and Markdown templates. See Tinderbox Training Video 34 - Exporting TBX Notes to PowerPoint PPTX with Pandoc.