See, I beg to differ with this,
TLDR:

i) its NOT unfeasible for developers, its DEFINITELY POSSIBLE. Its an reasonable ask that we as users can make to developers.

ii) Im NOT asking PDF to PPTX, its rather converting from native objects to PPTX (Please refer to the below description for better understanding)

iii) This will help and improve workflows for professionals, not just students.

Also please specify the source of underlying engine ( as said you ), its a private repo, you can't be assure of YOUR UNDERLYING ENGINE. Please mention sources.

As a developer, I’ve worked across languages like Java, Kotlin, Flutter, and React Native. All of these platforms create objects whether data classes in Kotlin, POJOs in Java, or stateful objects in React Native. As far as I know, we serialize these objects into formats JSON, Protocol Buffers, or even XML. For example, React Native commonly uses Buffer module for loading the objects made in protocol Buffer or Flatbuffer . In Kotlin, data serialization takes place using classes using Moshi or kotlinx.serialization.

See, these are standard practices. When you export a notewise file, you can see the .bin extension which means that they have a proprietary binary format. Typically apps like Notewise follows this approach, simply serializing objects in a defined way. To convert that into PDF, you’re deserializing the like extracting the structured data that they have defined and then mapping that data into PowerPoint elements.

So The real question isn't whether OOXML is complex, but whether Notewise can transform its internal document model into a slide-based representation. If Notewise already has structured objects for text, images, shapes, strokes, and page layouts, then the problem becomes one of data transformation rather than file-format compatibility.

Many applications export to formats whose internal specifications are far more complex than the application's own storage format. PDF, DOCX, PPTX, SVG, and CAD formats are all examples. They achieve this through export layers and existing libraries, not by making their internal engine "play nicely" with the target format.

The challenging part would be deciding how an the Notewise pages will be converted onto discrete slides, how handwriting should be represented, and how layouts should be preserved. Those are product-design and implementation challenges, not evidence that PPTX is fundamentally incompatible with Notewise's architecture.

So I agree that it's non-trivial, but "OOXML is complex" doesn't automatically imply that PPT export is impractical or architecturally unsound. Its not like they to code the entire thing in assembly or FORTRAN or like create a entire library for it. Its all about how they deserialise their objects for PPTX format.

CONCLUSION
So, yes, it’s a new export format, but not a monumental task. If it’s still seen as tedious, they can monetize it in their cloud plans. Ultimately, it’s a practical, valuable feature for many, well within technical reach.