SvelteSortOption config is ignored

"svelte.plugin.svelte.format.config.svelteSortOrder": "options-scripts-styles-markup"

formatting after setting this option still uses the default (style last)

[pushkine]

No, you can just add these non-default Svelte options to your .prettierrc file

This changes everything!

{ 
    "svelteSortOrder": "options-scripts-styles-markup" 
}

Putting this in .prettierrc does work after hitting F1 Svelte: Restart Language Server

[dummdidumm]

If there’s a .prettierrc present, all options of the extension are ignored

Does this mean users have to choose between having a .prettierrc file and non-default svelte options ?

No, you can just add these non-default Svelte options to your .prettierrc file.

If you don’t set the Svelte extension as the primary formatter for Svelte files […] then the Prettier extension is used for formatting

No it’s not

It may depend on your user setting on what is used in which case. For example this

{
  "editor.defaultFormatter": "esbenp.prettier-vscode"
}

means that the Prettier extension is used for all files. I don’t know what you got in there, though, because you can also overwrite this with

"[svelte]": {
    "editor.defaultFormatter": "svelte.svelte-vscode"
  }

Then the Svelte VS Code extension is used.