Maybe I'm misunderstanding something, but isn't SQL perfectly capable of acting on denormalized data? We often talk about the degree of normalization that a RDMS has. Perhaps this is in reference to nested data structures (which would normally be represented in RDMS via FK relations), but even there it's implementation dependent.
If you have nested data structures then it violates 1NF, i.e. the data isn't normalised.
Any "pure" RDBMS won't even be able to represent that denormalised data in a table, let alone query it with SQL. Normally this is worked around by straight up serialising it. Obviously some implementations have extensions, like Postgres has JSON columns.
SQL databases do indeed work with data not in Boyce-Codd-Normal-Form. :D
There exist indeed recent extensions of SQL that add support for denormalized data (arrays, objects), for example in Spark SQL and PostgreSQL, however SQL was originally designed for tables and it remains cumbersome to write complex queries on denormalized data (lateral views, etc).
A deeper and more detailed analysis of query languages for nested data can be found in our recent paper with a concrete use case in high energy physics, to be presented at VLDB 2022: