Defining a sequence as a list has been fully deprecated now, the other and simpler way is already possible since before Drupal 8.0.
Closed: duplicate
2.0
Code
Could it be that this is a duplicate of 📌 The definition for the 'core.entity_view_display.*.*.*.third_party_settings.layout_builder_restrictions' sequence declares the type of its items in a way that is deprecated in drupal:8.0.0 and is removed from drupal:11.0.0. Fixed ?