VSCode YAML/Markdown Indentation

I'm trying to indent my markdown and later some YAML with 4 spaces instead of the default 2, yet I can't seem to get this to work. I have the "Markdown All in One" extension by Yu Zhang installed, in addition to the "YAML" extension provided by RedHat. My current settings.json includes the following at the bottom:

"editor.tabSize": 4,
"editor.insertSpaces": true,
"editor.detectIndentation": false,
"[markdown]": {
    "editor.tabSize": 4
}

Any ideas? I don't see anything in the extension settings UI which appear to override this.