I have created a custom Drupal 8 module which defines a custom field type and the corresponding formatter and widget for that.
This field should be added by the admin to whichever Content Type he wants. The module's code, on specific occasions, will detect if this field type exists on a node and do some extra actions if it does.
Although the admin is responsible to add this custom field type to any CTs he likes, i would like to preset, with code, the internal settings of this field (e.g. make Allowed number of values = unlimited by default) and preferably lock the settings of the field altogether.
Scenario would be that admin adds the field to the desired CT and is allowed to make no changes to the field settings. This way the field will be securely configured, by the module itself, and the module's code would work as expected at all times without fear or extra checks that specific settings are not changed by the admin.
Is that possible and if yes how could it be implemented?