I don't know if this is what you want, but still...
It's not an IDE, and this works only for turning on highlighting for code snippets embedded in another textfile:
I think you can use Joplin or the App which is an Evernote clone with a few differences:
You write Markdown files
The synchronization backend is your choice
Inside the markdown files you can ...
Code Anywhere should work. It has an IOS and Web client and supports syntax highlighting plus many other features typically found in an IDE. Additionally, you can setup the file you want to be edited on Google Drive or an ftp server and use Code Anywhere to edit it from there.
Have you looked at kiki (https://sources.debian.org/src/kiki/0.5.6-8.1/). It's written in Python and uses wxPython, so likely could be run on numerous platforms. It's in Debian repositories, and possibly other Linux versions.
Although not free, there's a cheap (~5$) option - Data Transformer (disclaimer - I'm its developer). It converts between CSV, JSON, XML, and YML locally.
It offers a number of conversion settings (with sensible defaults) so you can match the data for your purposes.
You can check it out on the Mac App Store or the Microsoft Store.
Consider using a templating language such as Jinja (https://palletsprojects.com/p/jinja/) or Airspeed (https://github.com/purcell/airspeed) as your Markdown template. Then you simply need a little bit of code (both the links above are to Python libraries, so Python would be a sensible language to use) to read the CSV file and run it through the template to ...
If you were into R and modern R scripting:
You could use R's knitr package, write a little .Rmd file and "knit" the document to markdown+html (+ optionally .docx and pdf) in one fell swoop with the Rscript command line tool.
knitr has a "keep_md" option in the YAML front matter.
Together with the blogdown R package and static site generator Hugo you ...