Repeats in Power Automate are generally easy once you get a hold of the "uniquerowid" and "parentrowid" interaction.
Once you add a repeat to a survey, you will notice that there is an attribute called uniquerowid in your main table. Then, if you look at your repeat, you will notice it has two attributes for uniquerowid and parentrowid. You repeat's parentrowid will match your main table's uniquerowid. And you repeat's uniquerowid will be unique for each entry. If you have nested repeats, you keep repeating this process.
In Power Automate, you will need to use "Conditions" to avoid duplicates. Here is a screen cap from a nested repeat in Power Automate (i.e., a repeat within a repeat):
If you are able to provide your XLSX, I can give you a more relevant example.