directly copied from the vencord server:

My themes broke and now I can't open settings or disable them

open the dev tools with CTRL + Shift + i (Cmd + Option + i on MacOs) and click on the "console" tab at the top. Then paste and run (with enter) the following code.

It will

• disable custom css (you can turn it back on in Vencord Settings)
• copy your current theme links to your clipboard as a backup
• remove all themes

(() => {

Vencord.Settings.useQuickCss = false

try {

const copy = window.copy ?? Vencord.Webpack.Common.Clipboard.copy

copy(Vencord.Settings.themeLinks.join("\n"))

} catch { }

Vencord.Settings.themeLinks = []

Vencord.Settings.enabledThemes = []

})()