could you clarify what's exactly in your meaning "uniqueness of lines addition" and "that no empty lines are added"?

repeating section's lines are just containers for other controls.

you have to apply check on single controls. different type of controls need different approach...

The repeating section is considered as a work around for a grid lines control in other platforms.

so I am looking for each group of controls as a row on db table,

So when do add more rows I need to :

1- Make sure no empty controls is added.

2- for specific controls, should not be duplicated, ie. (as a primary key per line)

As seen below, I want to capture, the duplication on option 1 selection to be unique on the repeating section.

1. you can create a validation rule like: IsNullOrEmpty({Self})

and attach it to every single control

2. there is not OOTB functionality that would do that. you will have to write your own javascript code that implements your required logic.

very similar topic has been discussed here