Has anyone successfully taken a canva file and convert it into indesign?

Sorry - there's no easy way. There are some PDF converters that will convert PDFs to InDesign files - but far from ideal. 

You can then use Acrobats editing tools to edit the PDF.

https://www.adobe.com/acrobat/how-to/pdf-editor-pdf-files.html#:~:text=Use%20Acrobat%20editing%20tools%3A,watermark%20and%20annotate%20PDFs%20too.

You can edit Text (provided you have the fonts installed)

You can edit Vector Graphics by marqueing the vector object - and use Edit With and navigate to the Illustrator Application

Similary the same with Raster Images. 

You can replace images within the PDF - and you can do other things too. 

If you really needed to - you can place the Entire PDF in InDesign https://creativepro.com/placing-all-the-pages-of-a-pdf-inside-indesign/

And then overlay the new graphics/text etc on top of the old design (perhaps blank it out with a white background or another 'messy method'

Then overlay your new graphics/text.

You can then export the PDF with the updated changes. 

Not the best solutions - but there's ways and methods.

I'd get to like Canva. Or quit. 🙂

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so the optimal workflow is working from Illustrator to Canva via a series of SVGs or PDFs(likewise Indesign - Canva via PDFs), but not from Canva - unless you want to reverse engineer PDFs from Canva in Illustrator. Good luck.