It was rough a few years ago, but nowadays it's pretty nice. TI rebuilt their Code Composer Studio using Theia so it does have some larger users. It has LSP support and the same Monaco editor backend - which is all I need.
It's VSCode-with-an-Eclipse-feel to it - which might or might not be your cup of tea, but it's an alternative.
* https://code.visualstudio.com/Docs/languages/markdown#_inser...
I belong to the class of people who believe in customising their tools as they please. So I'd have written an Emacs package to do this. But then again, this is Emacs, so someone's probably already done it. Oh, here it is: https://github.com/mooreryan/markdown-dnd-images