I will confess my denseness, but I've read your explanation of what you
want several times, and I'm not sure I understand what you want. My
response below was to another user who was talking about using LyX. It
was not intended to address your original post as I don't understand
your desire.
What I *think* you're saying is that you want to write in Markdown, with
all the #Headings and *italics* code and then have LO automatically
convert that to its own formatted Headings and italics, etc. I don't
know of any converter (other than, perhaps, Pandoc) that can do that.
I have used a converter to go from ReStructuredText (a markup language
similar to Markdown) to .ODT, but it doesn't work very elegantly. One
reason is there are so many different way of formatting something in LO,
the converter doesn't know which way you might prefer. For example, LO
can format a heading directly or through paragraph styles with or
without automatic numbering. If you try to convert a Markdown #Heading
to LO, your converter won't know if you want direct formatting or
formatting with a paragraph style. My experience is that most converters
convert to direct formatting, which then means I have to go back and
change it all to styles, which sort of defeats the purpose of the
conversion.
You then mention wanting to create presentations from your Markdown.
There again I'm confused. Markdown's purpose is to be a front end to
HTML which is a continuous stream of content formatted for a web
browser. When I hear the word "presentation," I think in terms of LO
Impress or MS Powerpoint. Those formatted documents are *very* different
from what you get with HTML.
So, if you're trying to write in Markdown and end up with a document
that looks like a Powerpoint presentation, I think what you're asking
for is very ambitious, especially since Markdown wasn't intended for
that type of document. But, if you're using "presentation" in a
different sense, then I go back to my original comment, I don't
understand what you want.
Good luck with your efforts
Virgil