Mind you that vscode does have an ui to change the settings. Also it has code completion when editing the json because of the linked json schema.

It has a UI to change some of the settings. And not even all of the settings with autocomplete help - I have no idea why those aren't equivalent to each other at least as a fallback, but they very clearly are not. And plugins frequently have major settings documentation gaps, including absolutely massively used ones like Go.

Compare that to something like a JetBrains product.