Yes, repeater sub fields can be simple like “title” and can be duplicated in multiple repeaters.
The only limit to field names is naming sibling fields the same. All sibling field names must be unique.
What does that mean?
First it means that all “Top Level” fields in all field groups used on the same editor page must have unique.
It also means that all sub fields of the same parent must be unique.
Fields that have different parents, with unique field names do not need to be unique.
