You can remove presets one at a time, or as a batch, or you can remove the entire Customize > Presets tab. Add the code to your child theme's functions.php file.
Remove a single preset
Remove a preset with the following method:
As with adding a preset, removing a preset must also be done within the
Remove multiple presets
remove_preset function accepts arrays. Here's an example of code that will remove all of the built-in presets. You can modify the list of presets in the array to remove only a subset of them.