Custom WordPress Styles Variations for Block Themes using Plugin

Hello

I am looking to add custom styles variations using a custom plugin.

Here are the style variations for the 2024 WordPress theme.
https://ibb.co/svSZL6K

I want to add and modify these via plugin. I can do it using child themes or modifying the actual theme but not using the plugin.

Unfortunately the available filters do allow to override but do not provide any hook to show my custom style in the customizer as show in the screenshots attached

• wp_theme_json_data_default – Hooks into default data provided by WordPress.
• wp_theme_json_data_blocks – Hooks into data provided by blocks.
• wp_theme_json_data_theme – Hooks into data provided by the theme.
• wp_theme_json_data_user – Hooks into data provided by the user (custom).

Does any one have any idea how to show custom style variations in the WP Admin Dashboard?