Honestly, the full replication of the sort of integration with the old SNote app on Android (Samsung) from ten years ago would've been enough for me. When you set up the sync, and then each handwritten note you create in SNote (and now it would've been Nebo) would sync into an automatically created SNote sub-notebook in Evernote, as a note containing a single (or a set of) jpg image(s), that would be ocr-searchable in Evernote, and update automatically when you edit said notes in the original app.
That's it. If you tapped a synced like this note in Evernote on a device with SNote installed, it would launch the SNote app and open the note in question there to continue editing. If you tried opening the synced handwritten note in a browser, or on a device without the SNote app installed, then it would open as an non-editable note in Evernote, containing automatically synced images (or a pdf-file) of everything within it. You just wouldn't have to share anything extra manually to Evernote, and redo it all every time you make an edit in Nebo. It should do it for you, is all.
It's just... The bluepring for this is already *there*, and had been for a decade in Evernote by now. It's simple, it works, it's *enough*. It doesn't require hard-to-do integration, as well, just literally replicate the easiest solution you've done already, and watch your customer base grow exponentially with every stylus-loving user from every platform Nebo works on, please. It will also finally put an end to years of piling complaints of how abysmal Evernote Sketch/handwriting support is (especially on Samsung devices. It's honestly disgusting, the lack of palm rejection, or any development of the tool - and the lag on many a Samsung device or complete inability to natively work with an S Pen is so insufferable, it's just frustrating).
And Nebo would be interested in it too. They won't loose their customers, won't need to develop much, for any platform, and will be able to send everyone complaining that they *only* do handwriting and recognition well (while everything else functionality-wise in the native app is basically a joke) Evernote's way. It's literally the perfect symbiosis begging to happen.