It's likely possible for Kobo, but performance might be poor, as it is, Nebo (Advanced Notebooks) is abysmal on the Sage and Elipsa compared to Nebo on the Android tablet I have with a digitiser and pen or Nebo on the iPad plus Apple Pencil.
I'd doubt it's in the code. Kobo are certainly paying MyScript for Nebo. No idea if it's a percent or fixed fee per model sold or some other deal. Perhaps they tried it before Libra 2 release (the original Libra doesn't work) and decided it was too poor, so it's not included in the Firmware build.
You can make notes on the Libra 2 and save the *.svg files, copy those to PC/Mac/Android/iOS/Linux via USB and try handwriting OCR. The files even appear in "My Books" and can be viewed. You just can't edit them on the Libra 2 once you save.
In theory a 3rd party OCR or editor could be added like the way KOReader is added. No jailbreak needed. However a TCL Nxtpaper 11, TCL T-Pen and official cover is less than €300. 4G RAM, 128G Flash, 2000 x1200 pixels, SD card slot works up to 1T byte. True HD video and 200 fps.
Also Google's Gboard (at least Android 7 and later free from Playstore) does very good handwriting conversion even on an old 5.5″ phone, no digitiser needed (though can use a pen), but DO change all the default settings!
Note the Nebo on Kobo for notebooks is even more cut down than the free iPad version. There is no real time preview (which works well on TCL Nxtpaper 11 Android). Gboard also is real time. It's not viable on eink (I tried it on eink Android).
An old and iPad orientated review of Nebo, which Kobo is using for their notebooks. You can copy Kobo *.nebo files to iOS, Windows or Android and import and edit them in Nebo, but not vice-versa.
https://paperlike.com/blogs/paperlik...ebo-app-review