Well, not a production one, but we can pass a “lazy” generic command under linux and print the result within or without a simple Gtk buffer/layout/canvas, which might be an addon-like into Gramps!
e.g.,
$ tesseract -l fra input.jpg match digits # or paddleocr and whatever OCR engine will already provide something to help.
About zooming or image quality gain, I guess that gramps addons are more and less (often) for displaying (or going further). Edition or metadata stuff, Handwriting Text Recognition (HTR) could (might) be done via Editors or Tools. Or as mentioned by @StoltHD via external and more professional (specific) applications or environment.