Thie code snippet allows you to read the markdown cells in Jupyter notebooks and prints them. This should help when you want to spellcheck and vet the text.

notebook_markdown_to_text.py

import json

fn = 'notebook.ipynb'
notebook = json.load(open(fn))
notebook.keys()

for cell in notebook['cells']:
    if cell['cell_type'] == "markdown":
        for sent in cell['source']:
            if sent == '\n':
                continue
                
            print(sent)

You can copy the output into notion and it'll format it in correct markdown ;)