A repeating group will display the same thing in each cell, that’s the point of it.
Usually you use dynamic data in a repeating group, so each cell pulls the relevant data from the database to display the relevant item (each cell displays the same data from the database, but for a different ‘thing’).
In your video you’re using static data in the RG cell, that’s why it is the same in each cell.
If you want, or need, to use static data then there’s no need to use a repeating group, just use an ordinary group, then copy it and change the data in each one.
But, if you want to use a repeating group (which in most cases is more logical), then you need to store all your data in the database, and then pull it into the repeating group cell using dynamic data.