1NF bans relation-valued attributes, not repetition of attribute value across tuples in a relation. Mainstream SQL databases don't support relation-valued attributes, so any table you make in a relational database is 1NF.
You can push back on this a little - for instance maybe you consider an array-valued attribute to be enough like a relation to argue array-valued attributes violate 1NF. But if you do that you must also explain what makes arrays different from strings, since strings are pretty similar to arrays of characters and can be treated the same way in most respects (for instance characters in a string can be addressed by index or split into substrings).
You can push back on this a little - for instance maybe you consider an array-valued attribute to be enough like a relation to argue array-valued attributes violate 1NF. But if you do that you must also explain what makes arrays different from strings, since strings are pretty similar to arrays of characters and can be treated the same way in most respects (for instance characters in a string can be addressed by index or split into substrings).