This sounds like the same issue that caused me to switch from Google Docs to Markdown for my notes. One day I spent way too much time trying to figure out why I was getting errors when copy/pasting a command back to the command line. IIRC I finally copied the command to a `vim` window and found that GD was replacing consecutive spaces with some other character that the shell didn't interpret as a space.
Does turning off "Automatic Substitutions" (under Tools > Preferences > Substitutions) fix the problem? I have that turned off, as well as turning off "Smart quotes" (under the General tab) which drove me nuts with code fragments.
They may also add new options every now and then. I don't remember seeing the "Insert emojis using the colon character" option. Turned that damn thing off.
I'm not sure if you're if you're referring to G. Docs or not. I still use it for stuff that I need to share (and won't need to copy/paste to the CLI.) It did not occur to me at the time that there might be options to defeat Docs reformatting.
IAC Markdown and Mkdocs has been a solid platform for notes and with a private Gitea instance, all of my notes are local and private. Since MkDocs can serve the pages it produces, I can use it away from my home LAN (homelab) too, even w/out network access (though I suppose G. Docs has some way to cache documents locally. But I'd probably have to plan in advance.)
