How to remove text styles? And why "Normal" cannot be retrieved once changed?

Create a Preset that is "Normal".

Add a new Basic Title. If its current state is exactly what you want as "normal", then Select the Preset menu > Save All Format and Appearance Attributes. Otherwise, set up an initial text "state" to exactly what you want for the preset. Save the Preset as "Normal". Then, at any time you can reset the text to it's Normal Preset state and the Preset menu will display "Normal" as its heading.

Once you create the Preset in either app, it should be available in both (after restarts).

This particular feature is a little weird — you cannot overwrite a previous version of a preset, so you will have to follow LocaAlicia's recommendation to delete Text Style presets if you need to "start over".

1) Once you select a text style in Final Cut Pro, how to remove it to leave it blank?

Menu →Move+option →Library →Application Support →Motion →Library →Text style →Delete 3 files with the same name →Restart FCP

Just to try and clarify an issue with translation:

1) The menu in question is in Finder

2) The menu name in English is "Go", rather than "Move"

The menu name in English is "Go", rather than "Move"

Luis, thanks for the correction.👍