Regarding 2 issues about "Bad case", I think that MD format can be in simple var or class like:

1. string

j.cell = "# A minimal Markdown Jupyter notebook

This is a text cell
"
j.cell = 1+1

Then j.cell just can be hidden in notebook by special addon in options. And reason for list of all cells replacement can be like:

j.cell[0] = "# A minimal Markdown Jupyter notebook

This is a text cell
"
j.cell[1] = 1+1

a) or simple in configcell can be assigned as jupyter class cell = j() or cell = jupyter()
b) then simple enhancement to hide from j.cell[0] to j.cell[1] and j.cell[x] etc
c) issue around \newline
https://www.markdownguide.org/basic-syntax/#line-break-best-practices

2. Due proposal to make a cell as class from jupyter then this var can be decoreted I think as @jupyter

cells = [
  {
   "cell_type": "code",
   "execution_count": 11,
   "metadata": {},
   "outputs": [],
   "source": [],
  "widgets": [], # more vars to control jupyter
 "jupyter_class": ["j"], # class to reserve for jupyter decorator
"jupyter_cell": ["cell"], # var to reserve for jupyter notebook (to make hidden)
}
from ipyleaflet import Map, WMSLayer, SearchControl, Marker, AwesomeIcon ,ScaleControl, FullScreenControl, basemaps
j.cell[1] = 1+1
cell[1] = 1+1
j.cell[2] = 1+1
cell[2] = 1+1

3. Whole idea is about reflection to cells as internal in file, then option to control cells inside code as some tigers.
4. Ayway.. I think is no sense to parse python code from "" as json eg.

"1+1"

• Jupyter can take any line as cell if exist any string, then can be a vision for reflection for code without "" as code default.
  It's should be taken from default philosophy of IPython cmd line policy
• in case no assign array id/index then jupyter can do this, and the main role is to hide this as a paper notebok to export as pdf, etc. and input cell vision, in fact that doesn't matter how file looks, but.. (cod not as string where hard to edit

text = raw_input("prompt")  # Python 2
text = input("prompt")  # Python 3

Anyway.. it's better to have python object than json

Complicated? Noo..
Coz if "cell_type": "markdown" then just decorate it thas is not @cell but @md or @MD
There is no children/root in json .ipynb but stack down execution, json doing some complication due "pretty code" and it is far from python convention as indention.
For sectors as "cell_type": "markdown" exist quoting string, then no difference about assign var for json or as python object.

Soo...
Jupyter need change policy around:
outputs = cell output
source = cell input
Even this can be more interactive, then
outputs = cell output with assigned class as attachments eg.
@source
j.cell[2] = "x = 1+1"
@outputs
cell[2] = 2
@source
plotly = "x"
@attachment
cell[3] = "chart = plotly"

Of course need virtualize cells as lines.